CMV vaccines

ABSTRACT

Provided herein are genetically modified arenaviral vectors suitable as vaccines for prevention and treatment of cytomegalovirus infections and reactivation. Also provided herein are pharmaceutical compositions and methods for the treatment of cytomegalovirus infections and reactivation. Specifically, provided herein are pharmaceutical compositions, vaccines, and methods of treating cytomegalovirus infections and reactivation.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a U.S. National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/EP2014/076466, filed Dec. 3, 2014, which claims benefit of priority from U.S. Provisional Application No. 61/911,135 filed on Dec. 3, 2013 and U.S. Provisional Application No. 62/055,699 filed on Sep. 26, 2014 , which are incorporated herein by reference in their entireties.

1. INTRODUCTION

The invention relates to genetically modified arenaviruses suitable as vaccines for prevention and treatment of cytomegalovirus infections and reactivation. The invention also relates to pharmaceutical compositions and methods for the treatment of cytomegalovirus infections and reactivation. Specifically, provided herein are pharmaceutical compositions, vaccines, and methods of treating cytomegalovirus infections and reactivation.

2. BACKGROUND

2.1 Medical Need

Human cytomegalovirus (HCMV) is a ubiquitous beta-herpes virus that typically causes chronic latent, asymptomatic infection in healthy individuals, with overall age-adjusted CMV seroprevalence in the developed world of above 50% (Bate et al., Clin. Infect. Dis., 2010, 50(11):1439; La Rosa & Diamond, Future Virol., 2012, 7(3):279). However, in immunocompromised patients, especially transplant recipients, HIV-infected persons, and congenitally infected newborns, CMV causes significant morbidity and mortality and therefore poses an important public health problem.

HCMV infection is the most common cause of congenital viral infection in the developed world. Approximately 40,000 congenitally infected infants are born in the United States per year. Congenital CMV infection can result in a wide range of neurodevelopmental disabilities, and it presents the most common infectious cause of hearing loss in children. The large public health impact of HCMV is demonstrated by the fact that more children suffer from long-term sequelae as a result of congenital CMV infection than either Down syndrome or fetal alcohol syndrome (Cannon et al., BMC Public Health, 2005, 5:70).

In addition to its impact as a perinatal infection, HCMV is also an important cause of infectious complications in transplant patients, causing pneumonitis, hepatitis, gastrointestinal ulceration, retinitis and death. Although nowadays these severe forms of end organ disease can be prevented in most cases by the cost-intensive, routine use of preemptive therapy with antiviral drugs, late reactivation of CMV infection is still a problem. Furthermore, CMV triggers indirect effects such as graft rejection, accelerated atherosclerosis after heart or lung transplant or immunosuppression.

Moreover, CMV infection and/or reactivation are also significantly associated with mortality in HIV patients as well as in patients admitted to intensive care units.

2.2 HCMV Immunity and Vaccine Development

The significant public health impact of congenital CMV has led the US Institute of Medicine to rank development of a CMV vaccine as a top priority in its recent report “Vaccines for the 21st Century”. Although vaccine development efforts have been going on for several decades; so far there is no licensed CMV vaccine available. Development of an efficacious vaccine has been proven difficult as there are still critical gaps in the understanding of CMV epidemiology and transmission.

CMV rarely elicits disease in healthy immunocompetent hosts, where immunity against CMV provides some level of protection and plays an essential role in maintaining asymptomatic infection. However, the human immune system is unable to clear the infection and CMV usually establishes chronic infections that can persist lifelong despite host immunity. In contrast, uncontrolled CMV viremia and life-threatening symptoms readily occur after immunosuppression and in the immature host.

Several vaccine candidates based on different technologies have already been studied in clinical trials. Partial protection by vaccination has been demonstrated with both live-attenuated and glycoprotein vaccine candidates inducing CMV-specific antibody responses. Passive immunization with antibodies has also been shown to provide some protection. However, once latent infection has been established, strong induction of CMV-specific T cells seems to be necessary to control reactivation and disease.

2.3 HCMV Vaccine Antigens

Several data indicate that neutralizing antibodies inhibiting CMV entry into host cells play an important role for prevention of horizontal and vertical virus transmission. Studies based on neutralization of fibroblast infection have defined the major envelope glycoprotein B (gB) as one of the dominant targets of neutralizing antibodies. The inclusion of gB in a human CMV vaccine candidate is further supported by clinical phase II data showing that a subunit vaccine based on gB in combination with MF59 adjuvant is able to confer partial protection in seronegative women (Pass, J. Clin. Virol., 2009, 46(Suppl 4):573; Pass et al., N. Eng. J. Med., 2009, 360(12):1191).

Though vaccine candidates based on recombinant gB elicit high titers of neutralizing antibodies preventing HCMV infection, other HCMV antigens may elicit higher titers of antibodies that inhibit HCMV infection of particular cell types, such as epithelial and endothelial cells. A vaccine strategy for effective prevention of HCMV infection will likely depend on the ability to induce potent neutralizing antibodies inhibiting virus entry into various cell types. Recent studies have shown that a pentameric complex formed by the glycoproteins gH/gL (UL75/UL115), UL128, UL130, and UL131A is required for HCMV entry into epithelial and endothelial cells and is the target of potent neutralizing antibodies in HCMV-seropositive individuals (Ryckman et al., J. Virol., 2008, 82(1):60; Wang & Shenk, Proc. Natl. Acad. Sci. USA, 2005, 102:18153; Wussow, et al., J. Virol., 2013, 87(3):1322).

A potential vaccine antigen for the induction of protection against CMV disease mediated by cytotoxic T cells, is the tegument protein pp65 which is an immunodominant CD8+ T-cell antigen (Wills et al., J. Virol., 1996, 70(11):7569). pp65-specific CD8+ T-cell frequencies have been associated with immune control of CMV in transplant patients (Pipeling et al., J. Infect. Dis., 2011, 204(11):1663) and adaptive transfer of pp65-specific T cells appears to have therapeutic utility in hematopoietic stem cell transplant recipients (Peggs et al., Clin Infect Dis 2011, 52(1):49; Einsele et al., Blood, 2002, 99(11):3916; Micklethwaite et al., Blood, 2008, 112(10):3974). Taken together these findings suggest that a CMV vaccine designed to prevent CMV disease in transplant patients requires inclusion of pp65.

3. SUMMARY OF THE INVENTION

The invention relates to an infectious, replication-deficient arenavirus viral vector comprising a nucleotide sequence selected from the group consisting of:

-   -   a. a nucleotide sequence encoding a CMV glycoprotein gB or an         antigenic fragment thereof;     -   b. a nucleotide sequence encoding a CMV tegument protein pp65 or         an antigenic fragment thereof;     -   c. a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   d. a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   e. a nucleotide sequence encoding a CMV UL128 protein or an         antigenic fragment thereof;     -   f. a nucleotide sequence encoding a CMV UL130 protein or an         antigenic fragment thereof; and     -   g. a nucleotide sequence encoding a CMV UL131A protein or an         antigenic fragment thereof.

In certain embodiments, a viral vector as provided herein is infectious, i.e., is capable of entering into or inject its genetic material into a host cell. In certain more specific embodiments, a viral vector as provided herein is infectious, i.e., is capable of entering into or inject its genetic material into a host cell followed by amplification and expression of its genetic information inside the host cell.

In certain embodiments, the CMV glycoprotein gB or the antigenic fragment thereof is selected from SEQ ID NO: 3, SEQ ID NO: 6, SEQ ID NO: 9, SEQ ID NO: 12, SEQ ID NO: 15, SEQ ID NO: 18, SEQ ID NO: 21, SEQ ID NO: 24, SEQ ID NO: 27, and SEQ ID NO: 30 SEQ ID NO: 60, and SEQ ID NO: 63. In certain embodiments, the antigenic fragment is at least 10, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, or at least 900 amino acids long. In certain embodiments, the fragment is antigenic when it is capable of (i) eliciting an antibody immune response in a host (e.g., mouse, rabbit, goat, or donkey) wherein the resulting antibodies bind specifically to human CMV glycoprotein gB; and/or (ii) eliciting a specific T cell immune response.

In certain embodiments, the gB antigen comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the gB antigen or to an antigenic fragment selected from SEQ ID NO: 3, SEQ ID NO: 6, SEQ ID NO: 9, SEQ ID NO: 12, SEQ ID NO: 15, SEQ ID NO: 18, SEQ ID NO: 21, SEQ ID NO: 24, SEQ ID NO: 27, SEQ ID NO: 30, SEQ ID NO: 60, and SEQ ID NO: 63.

In certain embodiments, the pp65 antigen comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the pp65 antigen or antigenic fragment of SEQ ID NO: 36. In certain embodiments, the antigenic fragment is at least 10, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, or at least 500 amino acids long. In certain embodiments, the fragment is antigenic when it is capable of (i) eliciting an antibody immune response in a host (e.g., mouse, rabbit, goat, or donkey) wherein the resulting antibodies bind specifically to human CMV pp65; and/or (ii) eliciting a specific T cell immune response.

In certain embodiments, the glycoprotein gH comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the glycoprotein gH or antigenic fragment selected from SEQ ID NO: 39 and SEQ ID NO: 52. In certain embodiments, the antigenic fragment is at least 10, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, or at least 750 amino acids long. In certain embodiments, the fragment is antigenic when it is capable of (i) eliciting an antibody immune response in a host (e.g., mouse, rabbit, goat, or donkey) wherein the resulting antibodies bind specifically to human CMV glycoprotein gH; and/or (ii) eliciting a specific T cell immune response.

In certain embodiments, the glycoprotein gL comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the glycoprotein gL or antigenic fragment of SEQ ID NO: 41. In certain embodiments, the antigenic fragment is at least 10, 25, 50, 75, 100, 150, 200, 250, or at least 300 amino acids long. In certain embodiments, the fragment is antigenic when it is capable of (i) eliciting an antibody immune response in a host (e.g., mouse, rabbit, goat, or donkey) wherein the resulting antibodies bind specifically to human CMV glycoprotein gL; and/or (ii) eliciting a specific T cell immune response.

In certain embodiments, the UL128 comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the UL128 or antigenic fragment of SEQ ID NO: 43. In certain embodiments, the antigenic fragment is at least 10, 25, 50, 75, 100, at least 150 amino acids long. In certain embodiments, the fragment is antigenic when it is capable of (i) eliciting an antibody immune response in a host (e.g., mouse, rabbit, goat, or donkey) wherein the resulting antibodies bind specifically to human CMV UL128; and/or (ii) eliciting a specific T cell immune response.

In certain embodiments, the UL130 comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the UL130 or antigenic fragment of SEQ ID NO: 46. In certain embodiments, the antigenic fragment is at least 10, 25, 50, 75, 100, 150, 200, at least 250 amino acids long. In certain embodiments, the fragment is antigenic when it is capable of (i) eliciting an antibody immune response in a host (e.g., mouse, rabbit, goat, or donkey) wherein the resulting antibodies bind specifically to human CMV UL130; and/or (ii) eliciting a specific T cell immune response.

In certain embodiments, the UL131A comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the UL131A or antigenic fragment of SEQ ID NO: 48. In certain embodiments, the antigenic fragment is at least 10, 25, 50, 75, at least 100 amino acids long. In certain embodiments, the fragment is antigenic when it is capable of (i) eliciting an antibody immune response in a host (e.g., mouse, rabbit, goat, or donkey) wherein the resulting antibodies bind specifically to human CMV UL131A; and/or (ii) eliciting a specific T cell immune response.

In certain embodiments, the viral vector comprises at least two of:

-   -   a. a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   b. a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   c. a nucleotide sequence encoding a CMV UL128 protein or an         antigenic fragment thereof;     -   d. a nucleotide sequence encoding a CMV UL130 protein or an         antigenic fragment thereof; and     -   e. a nucleotide sequence encoding a CMV UL131A protein or an         antigenic fragment thereof,         wherein the two nucleotide sequences selected from a. to e.         above are separated by a nucleotide sequence that encodes a         self-cleaving peptide or an amino acid sequence that leads to         release of the upstream amino acid sequence by “ribosome         skipping” or a sequence element leading to binding of the         ribosome and translation of the downstream sequence such as         “internal ribosome entry sites”.

In certain embodiments, the viral vector comprises at least three of:

-   -   a. a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   b. a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   c. a nucleotide sequence encoding a CMV UL128 protein or an         antigenic fragment thereof;     -   d. a nucleotide sequence encoding a CMV UL130 protein or an         antigenic fragment thereof; and     -   e. a nucleotide sequence encoding a CMV UL131A protein or an         antigenic fragment thereof,         wherein the three nucleotide sequences selected from a. to e.         above are separated by a nucleotide sequence that encodes a         self-cleaving peptide or an amino acid sequence that leads to         release of the upstream amino acid sequence by “ribosome         skipping” or a sequence element leading to binding of the         ribosome and translation of the downstream sequence such as         “internal ribosome entry sites”.

In certain embodiments, the viral vector comprises at least four of:

-   -   a. a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   b. a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   c. a nucleotide sequence encoding a CMV UL128 protein or an         antigenic fragment thereof;     -   d. a nucleotide sequence encoding a CMV UL130 protein or an         antigenic fragment thereof; and     -   e. a nucleotide sequence encoding a CMV UL131A protein or an         antigenic fragment thereof,         wherein the four nucleotide sequences selected from a. to e.         above are separated by a nucleotide sequence that encodes a         self-cleaving peptide or an amino acid sequence that leads to         release of the upstream amino acid sequence by “ribosome         skipping” or a sequence element leading to binding of the         ribosome and translation of the downstream sequence such as         “internal ribosome entry sites”.

In certain embodiments, the viral vector comprises:

-   -   a. a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   b. a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   c. a nucleotide sequence encoding a CMV UL128 protein or an         antigenic fragment thereof;     -   d. a nucleotide sequence encoding a CMV UL130 protein or an         antigenic fragment thereof; and     -   e. a nucleotide sequence encoding a CMV UL131A protein or an         antigenic fragment thereof,         wherein the five nucleotide sequences a. to e. above are         separated by a nucleotide sequence that encodes a self-cleaving         peptide or an amino acid sequence that leads to release of the         upstream amino acid sequence by “ribosome skipping” or a         sequence element leading to binding of the ribosome and         translation of the downstream sequence such as “internal         ribosome entry sites”.

In certain embodiments, the self-cleaving peptide (or the ribosome-skipping sequence) can be obtained from a 2A protein from a member of the virus family Picornaviridae. In certain specific embodiments, the self-cleaving peptide (or the ribosome-skipping sequence) is obtained from (or derived from) Porcine teschovirus-1 2A, Thoseaasignavirus 2A, or Foot-and-mouth disease virus 2A peptide.

In certain embodiments, an open reading frame (ORF) of the arenavirus is deleted or functionally inactivated. In a specific embodiment, the ORF that encodes the glycoprotein GP of the arenavirus is deleted or functionally inactivated. In certain embodiments, functional inactivation of a gene eliminates any translation product. In certain embodiments, functional inactivation refers to a genetic alteration that allows some translation, the translation product, however, is not longer functional and cannot replace the wild type protein.

In certain embodiments, the viral vector can amplify and express its genetic information in a cell that has been infected by the viral vector but the viral vector is unable to produce further infectious progeny particles in a non-complementing cell. In certain embodiments, a viral vector as provided herein is infectious, i.e., is capable of entering into or inject its genetic material into a host cell. In certain more specific embodiments, a viral vector as provided herein is infectious, i.e., is capable of entering into or inject its genetic material into a host cell followed by amplification and expression of its genetic information inside the host cell.

In certain embodiments, the genomic information encoding the infectious, replication-deficient arenavirus particle is derived from the lymphocytic choriomeningitis virus (LCMV) Clone 13 strain or the LCMV MP strain. The nucleotide sequence of the S segment and of the L segment of Clone 13 are set forth in SEQ ID NOs: 32 and 33, respectively.

In certain embodiments, provided herein is a viral vector whose genome is or has been derived from the genome of Clone 13 (SEQ ID NOs: 32 and 33) by deleting an ORF of the Clone 13 genome (e.g., the ORF of the GP protein) and replacing it with a heterologous ORF that encodes an antigen (e.g., a CMV antigen) such that the remaining LCMV genome is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, or 100% identical to the nucleotide sequence of Clone 13 (SEQ ID NOs: 32 and 33).

In certain embodiments, provided herein is a viral vector whose genome has been derived from the genome of the LCMV strain MP (SEQ ID NOs: 49 and 53) by deleting an ORF of the LCMV strain MP genome (e.g., the ORF of the GP protein) and replacing it with a heterologous ORF that encodes an antigen (e.g., a CMV antigen) such that the remaining LCMV genome is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, at least 99.9% or 100% identical to the nucleotide sequence of LCMV strain MP (SEQ ID NOs: 49 and 53).

In a more specific embodiment, the viral vector comprises a genomic segment, wherein the genomic segment comprises a nucleotide sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, or 100% identical to the sequence of nucleotide 1639 to 3315 of SEQ ID NO: 31 or 1640 to 3316 of SEQ ID NO: 32. In certain embodiments, the viral vector comprises a genomic segment comprising a nucleotide sequence encoding an expression product whose amino acid sequence is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, or 100% identical to the amino acid sequence encoded by 1639 to 3315 of SEQ ID NO: 31 or 1640 to 3316 of SEQ ID NO: 32.

The invention also relates to an infectious, replication-deficient arenavirus particle comprising a nucleotide sequence encoding a CMV glycoprotein gB wherein the cytoplasmic domain of the glycoprotein gB has been deleted. In specific embodiments, the cytoplasmic domain of gB has been deleted. In other specific embodiments, the cytoplasmic domain of gB has been substituted with the cytoplasmic domain of a heterologous protein. In even other specific embodiments, the cytoplasmic domain and the transmembrane domain of gB have been substituted with the cytoplasmic domain and the transmembrane domain of a heterologous protein. In certain embodiments, the heterologous protein is the G protein of the Vesicular Stomatititis Virus (VSV) or the hemagglutinin protein of influenza virus. In certain embodiments, the growth or infectivity of the arenavirus is not affected by the heterologous amino acids. In specific embodiments, the transmembrane domain of the gB protein is deleted.

Also provided herein are nucleic acids encoding a fusion protein comprising a CMV glycoprotein gB or a fragment thereof and a heterologous polypeptide. In certain embodiments, the cytoplasmic domain of the glycoprotein gB has been deleted. In certain embodiments, the cytoplasmic domain of the glycoprotein gB has been substituted with the cytoplasmic domain of a heterologous protein. In even other specific embodiments, the cytoplasmic domain and the transmembrane domain of gB have been substituted with the cytoplasmic domain and the transmembrane domain of a heterologous protein. In certain embodiments, the heterologous protein is the G protein of VSV or the hemagglutinin protein of influenza virus. In certain embodiments, the transmembrane domain of the gB protein is deleted.

Also provided herein are fusion proteins comprising a CMV glycoprotein gB or a fragment thereof and a heterologous polypeptide. In certain embodiments, the cytoplasmic domain of the glycoprotein gB has been deleted. In certain embodiments, the cytoplasmic domain of the glycoprotein gB has been substituted with the cytoplasmic domain of the heterologous protein. In even other specific embodiments, the cytoplasmic domain and the transmembrane domain of gB have been substituted with the cytoplasmic domain and the transmembrane domain of a heterologous protein. In certain embodiments, the heterologous protein is the G protein of VSV or the hemagglutinin protein of influenza virus. In certain embodiments, the transmembrane domain of the gB protein is deleted.

Also provided herein are isolated nucleic acids, wherein the nucleic acid encodes an arenavirus genomic segment wherein one ORF of the genomic segment is deleted or functionally inactivated and wherein the genomic segment comprises one or any combination of:

-   -   a. a nucleotide sequence encoding a CMV glycoprotein gB or an         antigenic fragment thereof;     -   b. a nucleotide sequence encoding a CMV tegument protein pp65 or         an antigenic fragment thereof;     -   c. a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   d. a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   e. a nucleotide sequence encoding a CMV UL128 protein or an         antigenic fragment thereof;     -   f. a nucleotide sequence encoding a CMV UL130 protein or an         antigenic fragment thereof; and     -   g. a nucleotide sequence encoding a CMV UL131A protein or an         antigenic fragment thereof.

In certain embodiments, the genomic segment encoded by the isolated nucleic acid is the short segment, wherein the ORF encoding the GP is deleted. In certain embodiments, the genomic segment comprises a CMV glycoprotein gB or a fragment thereof. In certain embodiments, the cytoplasmic domain of the glycoprotein gB has been deleted. In certain embodiments, the cytoplasmic domain of the glycoprotein gB has been substituted with the cytoplasmic domain of a heterologous protein. In specific embodiments, the heterologous protein is the G protein of VSV or the hemagglutinin protein of influenza virus. In certain embodiments, the transmembrane domain of the gB protein is deleted. In certain embodiments, the cytoplasmic and transmembrane domains of the glycoprotein gB have been substituted with the cytoplasmic domain and the transmembrane domain of the heterologous protein.

In one aspect, provided herein are methods for generating an infectious, replication-deficient arenavirus particle comprising:

-   -   a. transfecting into a host cell a nucleic acid described         herein;     -   b. maintaining the host cell under conditions suitable for virus         formation; and     -   c. harvesting the infectious, replication-deficient arenavirus         particle;         wherein the host cell expresses the ORF that is deleted or         functionally inactivated on the genomic segment. In certain         embodiments, any additional nucleic acids required for the         resuce of a viral particle are also transfected into the host         cell in step a. Such additional nucleic acids can be: the cDNA         of the second arenavirus genomic segment, a nucleic acid         encoding the L ORF, and/or a nucleic acid encoding the N ORF.

In another aspect, provided herein are compositions, e.g., pharmaceutical, immunogenic or vaccine compositions, comprising a viral vector described herein and a pharmaceutically acceptable carrier. Also provided herein are compositions (e.g., vaccine compositions) that comprise two or more different viral vectors described herein (i.e., wherein the viral vectors encode different CMV antigens). In certain embodiments, the pharmaceutical composition comprises a nucleic acid or fusion protein described herein.

In a further aspect, provided herein are methods of treating or preventing CMV infection or reactivation in a patient, comprising administering to the patient a viral vector, a pharmaceutical composition, an immunogenic composition, or a vaccine described herein. In yet another aspect, provided herein is use of a viral vector, a pharmaceutical composition, an immunogenic composition, or a vaccine described herein for the treatment or prevention of CMV infection or reactivation in a patient. In certain embodiments, an infectious, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof is capable of preventing transmission and/or infection of CMV from a mother to an unborn child. In certain embodiments, one or more infectious, replication-deficient arenaviruses expressing a CMV antigen or a fragment thereof are capable of preventing transmission and/or infection of CMV from a mother to an unborn child.

In certain embodiments, administering to a patient an infectious, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof induces a long-lasting immune response.

In certain embodiments, provided herein are methods of treating and or preventing CMV infection or reactivation in a patient, comprising administering to the patient two or more replication-deficient arenaviruses expressing a CMV antigen or fragment thereof. In a more specific embodiment, each replication-deficient arenavirus expresses a different CMV antigen or fragment thereof. In other embodiments, each replication-deficient arenavirus expresses a CMV antigen or a derivative thereof. In some embodiments the derivative thereof is a CMV antigen fragment. In yet another embodiment provided herein are compositions that comprise two or more replication-deficient arenaviruses each expressing a different CMV antigen or fragment thereof.

In certain embodiments, provided herein is a recombinant LCMV strain MP.

In certain embodiments, provided herein is an isolated nucleic acid encoding an amino acid sequence selected from the group consisting of (i) at least 99% or 100% identical to SEQ ID NO: 54; (ii) at least 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO:55; (iii) at least 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 56; and (iv) at least 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 57.

In certain embodiments, provided herein is an expression vector comprising a nucleic acid encoding an amino acid sequence selected from the group consisting of (i) at least 99% or 100% identical to SEQ ID NO: 54; (ii) at least 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 55; (iii) at least 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 56; and (iv) at least 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 57.

In certain embodiments, provided herein is a host cell comprising an expression vector comprising a nucleic acid encoding an amino acid sequence selected from the group consisting of (i) at least 99% or 100% identical to SEQ ID NO: 54; (ii) at least 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 55; (iii) at least 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 56; and (iv) at least 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 57.

In certain embodiments, provided herein is an isolated protein comprising an amino acid sequence selected from the group consisting of (i) at least 99% or 100% identical to SEQ ID NO: 54; (ii) at least 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 55; (iii) at least 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 56; and (iv) at least 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 57.

In certain embodiments, provided herein is an antibody immunospecifically binding to a protein comprising an amino acid sequence selected from the group consisting of (i) at least 99% or 100% identical to SEQ ID NO: 54; (ii) at least 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 55; (iii) at least 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 56; and (iv) at least 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 57.

In certain embodiments, provided herein is an isolated nucleic acid comprising the nucleotide sequence of SEQ ID NO: 49 or 53. In one embodiment, provided herein is an expression vector comprising the nucleic acid. In one embodiment, provided herein is a host cell comprising the nucleic acid or the expression vector. In one embodiment, provided herein is a recombinant viral vector comprising the nucleotide sequence of SEQ ID NO: 49 or 53.

In one embodiment, provided herein is a vaccine composition HCMV gB protein wherein the cytoplasmic domain of HCMV gB is deleted. In one embodiment, the truncated HCMV gB comprises the N-terminal 772 amino acids of gB strain Merlin (SEQ ID NO: 60) but does not comprise the remaining C-terminal amino acids of gB strain Merlin. In one embodiment, the truncated HCMV gB consists essentially of the N-terminal 772 amino acids of gB strain Merlin (SEQ ID NO: 60). In one embodiment, the truncated HCMV gB consists essentially of the N-terminal 772 amino acids of gB strain Merlin (SEQ ID NO: 60) followed by an Arginin residue at position 773. In one embodiment, the truncated HCMV gB comprises an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, at least 99.5% or 100% identical to the amino acid sequence of SEQ ID NO: 18.

In certain embodiments, provided herein is an infectious, replication-deficient arenavirus viral vector engineered to contain a genome with the ability to amplify and express its genetic information in infected cells but unable to produce further infectious progeny particles in normal, not genetically engineered cells, wherein one arenavirus open reading frame is removed and replaced by a nucleotide sequence encoding a CMV antigen or an antigenic fragment thereof, wherein administration of the arenavirus viral vector to a subject induces a long-lasting immune response against the CMV antigen or an antigenic fragment thereof. In certain embodiments, the long-lasting immune response induces a detectable antibody titer against the CMV glycoprotein gB or an antigenic fragment thereof. In certain embodiments, the long-lasting immune response induces a detectable antibody titer against the CMV antigen or an antigenic fragment thereof for at least a minimum of 4 weeks. In certain embodiments, the long lasting immune response increases the antibody titer against the CMV antigen or an antigenic fragment thereof by at least 100%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000%.

In certain embodiments, provided herein is an infectious, replication-deficient arenavirus viral vector engineered to contain a genome with the ability to amplify and express its genetic information in infected cells but unable to produce further infectious progeny particles in normal, not genetically engineered cells, wherein one arenavirus open reading frame is removed and replaced by a nucleotide sequence encoding a CMV antigen or an antigenic fragment thereof, wherein the arenavirus viral vector is suitable to protect against a congenital CMV infection. In certain embodiments, the congenital CMV infection is symptomatic. In certain embodiments, the congenital CMV infection is asymptomatic. In certain embodiments, the arenavirus vector reduces congenital CMV infection in a subject by at least about 10%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90% or more. In certain embodiments, the arenavirus virus vector reduces manifestations of congenital CMV. In certain embodiments, the manifestations include: mental retardation, blindness and sensorineural deafness, microcephaly, chorioretinitis, intracranial calcifications, hepatosplenomegaly, hepatitis, jaundice, direct hyperbilirubinemia, thrombocytopenia, petechiae, oligohydramnios, polyhydramnios, prematurity, intrauterine growth retardation, nonimmune hydrops, fetal ascites, hyptonia, and anemia, as a result of congenital CMV infection.

3.1 Conventions and Abbreviations

APC Antigen presenting cells C-cell Complementing cell line CD4 Cluster of Differentiation 4 CD8 Cluster of Differentiation 8 CMI Cell-mediated immunity CMV Cytomegalovirus Flu-HA Influenza hemagglutinin gB Glycoprotein B GP Glycoprotein GS-plasmid Plasmid expressing genome segments HRP Horse radish peroxidase IFN-γ Interferon-γ LCMV Lymphocytic choriomeningitis virus MHC Major Histocompatibility Complex NP Nucleoprotein ORF Open reading frame T2A Teschovirus 2A TF-plasmid Plasmid expressing transacting factors TNF-α Tumor necrosis factor-α UTR Untranslated region VSV-G Vesicular stromatitis virus protein G Z Matrix Protein from LCMV HK1 constructs (ie, Obtained or derived from LCMV Clone 13 name includes HK1) HK3 constructs (ie, Obtained or derived from MP strain of LCMV name includes HK3)

4. DESCRIPTION OF THE SEQUENCE LISTING

The following sequences are illustrative amino acid sequences and nucleotide sequences that can be used with the methods and compositions described herein. In some instances a DNA sequence is used to describe the RNA sequence of a viral genomic segment. The RNA sequence can be readily deduced from the DNA sequence.

SEQ ID NO: 1 is the nucleotide sequence of HK1-HgB(FL) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO: 1 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 1 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 2 is the nucleotide sequence for HgB(FL) cDNA.

SEQ ID NO: 3 is the amino acid sequence for HgB(FL).

SEQ ID NO: 4 is the nucleotide sequence of HK1-HgB(dTM) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO: 4 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 4 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 5 is the nucleotide sequence for HgB(dTM) cDNA.

SEQ ID NO: 6 is the amino acid sequence for HgB(dTM).

SEQ ID NO: 7 is the nucleotide sequence of HK1-HgB(1-706) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO:7 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO:7 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 8 is the nucleotide sequence for HgB(1-706) cDNA.

SEQ ID NO: 9 is the amino acid sequence for HgB(1-706).

SEQ ID NO: 10 is the nucleotide sequence of HK1-HgB(1-691) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO:10 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 10 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 11 is the nucleotide sequence for HgB(1-691) cDNA.

SEQ ID NO: 12 is the amino acid sequence for HgB(1-691).

SEQ ID NO: 13 is the nucleotide sequence of HK1-HgB(1-447) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO: 13 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 13 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 14 is the nucleotide sequence for HgB(1-447) cDNA.

SEQ ID NO: 15 is the amino acid sequence for HgB(1-447).

SEQ ID NO: 16 is the nucleotide sequence of HK1-HgB(dCt) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO:16 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO:16 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 17 is the nucleotide sequence for HgB(dCt) cDNA.

SEQ ID NO: 18 is the amino acid sequence for HgB(dCt).

SEQ ID NO: 19 is the nucleotide sequence of HK1-HgB(VSV-G-1) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO:19 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO:19 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 20 is the nucleotide sequence for HgB(VSV-G-1) cDNA.

SEQ ID NO: 21 is the amino acid sequence for HgB(VSV-G-1).

SEQ ID NO: 22 is the nucleotide sequence of HK1-HgB(VSV-G-2) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO:22 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO:22 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 23 is the nucleotide sequence for HgB(VSV-G-2) cDNA.

SEQ ID NO: 24 is the amino acid sequence for HgB(VSV-G-2).

SEQ ID NO: 25 is the nucleotide sequence of HK1-HgB(H3-1) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO: 25 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 25 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 26 is the nucleotide sequence for HgB(H3-1) cDNA.

SEQ ID NO: 27 is the amino acid sequence for HgB(H3-1).

SEQ ID NO: 28 is the nucleotide sequence of HK1-HgB(H3-2) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO: 28 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 28 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 29 is the nucleotide sequence for HgB(H3-2) cDNA.

SEQ ID NO: 30 is the amino acid sequence for HgB(H3-2).

SEQ ID NO: 31 is the lymphocytic choriomeningitis virus segment S, complete sequence. The genomic segment is RNA, the sequence in SEQ ID NO: 31 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO:31 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 32 is the lymphocytic choriomeningitis virus clone 13 segment S, complete sequence (GenBank: DQ361065.2). The genomic segment is RNA, the sequence in SEQ ID NO: 32 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 32 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 33 is the lymphocytic choriomeningitis virus clone 13 segment L, complete sequence (GenBank: DQ361066.1). The genomic segment is RNA, the sequence in SEQ ID NO: 33 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 33 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 34 is the nucleotide sequence of HK1-Hpp65 genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO: 34 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 34 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 35 is the nucleotide sequence for Hpp65 cDNA.

SEQ ID NO: 36 is the amino acid sequence for Hpp65.

SEQ ID NO: 37 is the nucleotide sequence of HK1-HgH genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO: 37 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 37 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 38 is the nucleotide sequence for HgH cDNA.

SEQ ID NO: 39 is the amino acid sequence for HgH.

SEQ ID NO: 40 is the nucleotide sequence for HgL cDNA.

SEQ ID NO: 41 is the amino acid sequence for HgL.

SEQ ID NO: 42 is the nucleotide sequence for HUL128 cDNA.

SEQ ID NO: 43 is the amino acid sequence for HUL128.

SEQ ID NO: 44 is the nucleotide sequence of HK1-HUL130 genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO: 44 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 44 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 45 is the nucleotide sequence for HUL130 cDNA.

SEQ ID NO: 46 is the amino acid sequence for HUL130.

SEQ ID NO: 47 is the nucleotide sequence for HUL131A cDNA.

SEQ ID NO: 48 is the amino acid sequence for HUL131A.

SEQ ID NO: 49 is the lymphocytic choriomeningitis strain MP segment L, complete sequence. The genomic segment is RNA, the sequence in SEQ ID NO:49 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO:49 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 50 is the nucleotide sequence of HK1-HgH(dTM) genomic segment. The genomic segment is RNA, the sequence in SEQ ID NO:50 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO:50 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 51 is the nucleotide sequence for HgH(dTM) cDNA.

SEQ ID NO: 52 is the amino acid sequence for HgH(dTM).

SEQ ID NO: 53 is the lymphocytic choriomeningitis strain MP segment S, complete sequence. The genomic segment is RNA, the sequence in SEQ ID NO:53 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO:53 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 54 is the amino acid sequence of the NP protein of the MP strain of LCMV.

SEQ ID NO: 55 is the amino acid sequence of the GP protein of the MP strain of LCMV.

SEQ ID NO: 56 is the amino acid sequence of the L protein of the MP strain of LCMV.

SEQ ID NO: 57 is the amino acid sequence of the Z protein of the MP strain of LCMV.

SEQ ID NO: 58 is the sequence of LCMV clone 13 S-Segment encoding HCMV strain Merlin gB; full-length wildtype. The genomic segment is RNA, the sequence in SEQ ID NO: 58 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 58 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 59 is the cDNA sequence of HCMV strain Merlin gB(FL) ORF.

SEQ ID NO: 60 is the amino acid sequence of HCMV strain Merlin gB(FL).

SEQ ID NO: 61 is the sequence of LCMV clone 13 S-Segment encoding HCMV strain Merlin gB sequence; deletion of transmembrane region (dTM). The genomic segment is RNA, the sequence in SEQ ID NO: 61 is shown for DNA; however, exchanging all thymidines (“T”) in SEQ ID NO: 61 for uridines (“U”) provides the RNA sequence.

SEQ ID NO: 62 is the cDNA sequence of HCMV strain Merlin gB(dTM) ORF.

SEQ ID NO: 63 is the amino acid sequence of HCMV strain Merlin gB(dTM).

5. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1: The genome of wild type arenaviruses consists of a short (1; ˜3.4 kb) and a large (2; ˜7.2 kb) RNA segment. The short segment carries ORFs encoding the nucleoprotein (3) and glycoprotein (4). The large segment encodes the RNA-dependent RNA polymerase L (5) and the matrix protein Z (6). Wild type arenaviruses can be rendered replication-deficient vaccine vectors by deleting the glycoprotein gene and inserting, instead of the glycoprotein gene, antigens of choice (7) against which immune responses are to be induced.

FIG. 2: (Adapted from Potzsch, et al., 2011) Antigenic sites of gB protein expressed in various different rLCMV-gB vectors; AS-1/5 refer to the antigenic sites 1-5 of glycoprotein B. TM indicates the transmembrane domain of gB. Crossed-out scissors indicate a mutation in the furin-cleavage site located within the ectodomain of gB. “H” in vector names (e.g. HK1-HgB(FL)) indicate human CMV gB sequences; “GP” in vector names (e.g. HK1-GPgB(FL)) indicate guinea pig CMV gB sequences.

FIG. 3A: Different rLCMV-PC vectors are generated for the expression of membrane-anchored (wildtype) or non-anchored (transmembrane domain deleted) forms of either the entire pentameric complex or just parts thereof. Arrows in individual colors indicate 2A self-cleaving sequences. The 2A nucleotide sequence was wobbled to avoid homologous recombination while plasmid cloning or in the context of the vector backbone.

FIG. 3B: Different rLCMV-PC vectors are generated for the expression of membrane-anchored (wildtype) or non-anchored (transmembrane domain deleted) forms of either the entire pentameric complex or just parts thereof 2A self-cleaving sequences separating the individual PC components were wobbled for the reasons outlined above. Alternatively, an IRES sequence was placed between two open reading frames (ORF) leading to translation of the downstream ORF. Further, a protein tag (V5) was fused to individual pentamer complex proteins to facilitate detection in Western blotting. 2A*: 2A peptide derived from a 2A protein from a member of the virus family Picornaviridae (e.g., Porcine teschovirus-1 2A, Thosea asigna virus 2A).

FIG. 4: LCMV GP expressing HEK 293 suspension cultures were infected with rLCMV vectors HK1-HgB(FL), HK1-HgB(dTM), HK1-HgB(706), HK1-HgB(691), HK1-HgB(dCt), HK1-HgB(VSVG-1), HK1-HgB(VSVG-2), HK1-HgB(H3-1) and HK1-HgB(H3-2) (MOI of 0.001). A corresponding rLCMV vector expressing the green-fluorescent-protein (HK1-GFP) has been used as control. (A) Viral infection was monitored in focus forming units (FFU) assay by counting stained foci after 72 h or 96 h of incubation. Results were used to determine the viral titer by calculating the number of focus forming units per milliliter (FFU/ml). (B) To assess the infectivity of vector particles, vector RNA was isolated from stock preparations and the amount of genome equivalents was determined using quantitative real time PCR (qPCR). Respective results were put in correlation with FFU titers established in (A) to calculate the specific infectivity of the vector constructs.

FIG. 5: In order to analyze vector replication, growth curves were performed using suspension HEK 293 cells expressing LCMV GP. Respective cells were seeded with cell density of 3×10⁵ cells/ml and infected with individual vectors (HK1-HgB(dTM), HK1-HgB(dCt), HK1-HgB(VSVG-1), HK1-HgB(H3-2) and HK1-HgB(691)) at MOI of 0.001. Samples were drawn every 24 hours and analysed by FFU assay. All tested vectors exhibited similar growth kinetics and peak titers compared to HK1-GFP indicating that the individual gB transgenes did not interfere with vector replication to a greater extent than the small reportergene GFP.

FIG. 6: HEK 293 cells expressing LCMV GP were infected with individual rLCMV-gB constructs (HK1-HgB(VSVG-1), HK1-HgB(VSVG-2), HK1-HgB(H3-1), HK1-HgB(H3-2), HK1-HgB(dCt), HK1-HgB(FL), HK1-HgB(dTM)) at a multiplicity of infection (MOI) of 0.001. Cells were analyzed 96 h post infection. Proteins were separated on SDS gels, transferred to nitrocellulose membranes and gB protein expression was detected with transgen specific primary (Mouse monoclonal antibody to human CMV gB) and appropriate secondary antibody. Uncleaved precursors of full length gB are expected to band at ˜160 kDa whereas cleaved gB contains a surface component with an estimated molecular mass of 116 kDa that is linked by disulfide bonds to a transmembrane component with an estimated molecular mass of 55 kDa. However, due to use of a monoclonal primary antibody only two bands representing the uncleaved gB protein and the smaller cleavage product of gB are expected to be visible on the blot. As expected, full length gB (lane 7) banded at ˜160 kDa, whereas all remaining constructs showed bands of lower size which can be explained by the deletion or exchange of at least parts of the gB cytoplasmic domain. Analogously, the transmembrane part of full length gB (lane 7) bands at ˜60 kDa (slightly higher than expected) and all gB derivates exhibit cleavage products of lower size. In general HK1-gB(FL) and HK1-gB(dTM) exhibited weaker gB bands compared to all other vectors.

FIG. 7: C57BL/6 mice were immunized subcutaneously 3 times on days 0, 21 and 42 of the experiment with 6.7×10⁴ FFU/dose of each of HK1-GPgB-dTM, HK1-GPgB-dTMuc, HK1-GPgB-FL and with 9.2×10⁵ FFU/dose of HK1-GFP. Sera of immunized mice were collected on days 21, 42 and 63 of the experiment and anti-GPgB IgG antibody titers were determined by ELISA. Endpoint GMTs are shown.

FIGS. 8A and B: C57BL/6 mice were immunized 3 times on days 0, 21 and 42 of the experiment either via the intramuscular route (FIG. 8A) or by subcutaneous injections (FIG. 8B) with different concentrations (7.4×10′, 2.2×10³, 6.7×10⁴ and 2×10⁶ FFU/dose) of HK1-GPgB-dTM. Sera of immunized mice were collected on days 21, 42 and 63 of the experiment and anti-GPgB IgG antibody titers were determined by ELISA. Endpoint GMTs are shown.

FIG. 8C: C57BL/6 mice were immunized with 5,6×10⁵ (groups 1 and 3) or 3,2×10³ (groups 2 and 4) FFU/dose of HK1-HgB(dCt) on days 0 and 28 via the intramuscular (Groups 1 and 2) or the intradermal (Groups 3 and 4) route. Sera of immunized mice were collected on day 28, 56 and 70 and anti-HCMVgB IgG antibody titers were measured by ELISA. Monoclonal antibody equivalent concentrations (μg/ml) are shown; a monoclonal anti-gB antibody (mIgG1) has been used for standard curve generation.

FIG. 8D: C57BL/6 mice were immunized with 6,7×10⁵ (Groups 1 and 3) or 3.5×10³ (Groups 2 and 4) FFU/dose of HK1-Hpp65 on days 0 and 28 via the intramuscular (Groups 1 and 2) or the intradermal (Groups 3 and 4) route. CD8+ T cell responses were analyzed by flow cytometry restimulating spleen cells with a pool of peptides generated based on Shedlock D. et al (Human Vaccines & Immunotherapeutics 2012; 8:11, 1-14) on day 38. Control cells were stimulated with medium only. After incubation with medium (lanes 1-4) or with specific peptides (lanes 5-8) cells were stained for flow cytometric analysis of CD8+ T cells. Expression of IL-2, IFN-g and TNF was analyzed.

FIG. 9: C57BL/6 mice were immunized intramuscularly with 1×10⁵ FFU/dose of HK1-HgB(691), HK1-HgB(706), HK1-HgB(dCt), HK1-HgB(H3-1), HK1-HgB(H3-2), HK1-HgB(VSVG-1), HK1-HgB(VSVG-2), HK1-HgB(dTM) and recombinant gB/adjuvant on days 0 and 21. Sera of immunized mice were collected on days 0, 21, 42, 63, 84 and 105 of the experiment and anti-HCMVgB IgG antibody titers were measured by ELISA. Endpoint GMTs are shown.

FIG. 10: C57BL/6 mice were immunized intramuscularly with 1×10⁵ FFU/dose of HK1-HgB(691), HK1-HgB(706), HK1-HgB(dCt), HK1-HgB(H3-1), HK1-HgB(H3-2), HK1-HgB(VSVG-1), HK1-HgB(VSVG-2), HK1-HgB(dTM) and recombinant gB/adjuvant on days 0 and 21. Sera collected on day 42 were mixed with media containing guinea pig complement (final concentration: 5%) and GFP-tagged HCMV strain TS15-rN. Serum/media mixtures were incubated for 60 min at 37° C., and then transferred to wells of a 384-well plate containing ARPE-19 cells. Representative micrographs were taken on day 4 and GFP was quantitated on day 7 post infection. GFP values were plotted vs. serum concentration and analyzed using four-parameter curve fitting to determine approximate dilutions that result in 50% inhibition. Logarithmic reciprocal neutralization titers (IC50) are presented.

FIG. 11: C57BL/6 mice were immunized intramuscularly with 1×10⁵ FFU/dose of HK1-HgB(691), HK1-HgB(706), HK1-HgB(H3-2), HK1-HgB(VSVG-1), HK1-HgB(dTM) and recombinant gB/adjuvant on days 0 and 21. Sera collected on day 42 were analyzed by HCMVgB-specific IgG subclass ELISA. The percentage of HCMVgB-specific IgG subclasses was calculated as the ratio of the individual subclass Endpoint Titer GMT divided by the total Endpoint Titer GMT of all subclasses.

FIG. 12: Hartley guinea pigs (4 animals/group) were immunized intramuscularly with different concentrations (1.54×10⁷, 1.54×10⁶, 1.54×10⁵ and 1.54×10⁴ FFU/dose) of HK1-GPgB-dTM on days 0, 21 and 42. Sera of immunized animals were collected on days 0, 21, 42 and 63 of the experiment and anti-gB antibody titers were analyzed by GPgB-specific IgG ELISA. Endpoint GMTs are shown. The lone filled circle indicates GPCMV positive control serum.

FIG. 13: Hartley guinea pigs (4 animals/group) were immunized intramuscularly with different concentrations (1.54×10⁷, 1.54×10⁶, 1.54×10⁵ and 1.54×10⁴ FFU/dose) of HK1-GPgB-dTM on days 0, 21 and 42. The neutralizing activity of anti-GPgB antibodies in the sera of immunized animals collected on day 63 of the experiment was analyzed by plaque reduction assay.

FIG. 14: LCMV GP-expressing HEK 293 suspension cells were infected with rLCMV vector HK1-Hpp65 (MOI=0.001). A rLCMV vector expressing GFP (HK1-GFP) was used as a control. Samples were drawn at indicated time points and were analyzed by FFU assay (A) to calculate the number of focus forming units (FFU) per sample unit volume (FFU/ml) and by qPCR to calculate the specific infectivity of the vector constructs (B).

FIG. 15: LCMV GP-expressing HEK 293 suspension cells were infected with HK1-Hpp65 or a negative control vector HK1-GFP, harvested and lysed 96 h post infection, separated on SDS gels, transferred to nitrocellulose membranes and probed with anti-pp65 primary and appropriate alkaline phosphatase conjugated secondary antibody. Human CMV pp65 protein is expected to band in the range of 65 kDa, corresponding to the main band of HK1-Hpp65 in Western Blot.

FIG. 16: (A) and (B) Groups of 15 C57BL/6 mice were vaccinated intramuscularly (100 μL/mouse in total; 50 μL /thigh) with a target dose of 1×10⁴ of HK1-Hpp65 (Group 1) or HK3-Hpp65 (Group 2). Non-vaccinated mice (Group 7) were used as a control. For the determination of T cell responses cytokines were analysed by flow cytometry. On day 10 after immunization, 5 mice/group were sacrificed and single cell suspension of spleen cells were restimulated with a pool of peptides generated based on Shedlock D. et al (Human Vaccines & Immunotherapeutics 2012; 8:11, 1-14). After 5 hrs stimulation time the cells were stained for flow cytometric analysis of CD4+ and CD8+ T cells. The cells were stained for the surface marker CD3, CD4 and CD8. After 30 min of surface staining, the cells were permeabilized with 2% PFA (15 min) and treated with saponin to ensure that the cell surface stays permeable. After 30 min intracellular staining (IL-2, IFN-g and TNF-a) samples were washed and measured with FACS Gallios. The frequency of cytokine-expressing CD4+ (A) or CD8+ T (B) cells is reported. (C) Groups of 10 C57BL/6 mice were vaccinated twice by the intramuscular route with a target dose of 1×104 of HK1-HgB(dTM) on days 0 and 28 of the experiment. On day 56 of the experiment mice were vaccinated intramuscularly with a target dose of 1×10⁴ of HK1-Hpp65 (Group 3) or HK3-Hpp65 (Group 4). Non-vaccinated mice (Group 7) were used as a control. On day 66 of the experiment T cell responses were analysed by measuring cytokines by flow cytometry. Single cell suspension of spleen cells from sacrificed mice (5/group) were restimulated with the same pool of peptides. After 5 hrs stimulation time the cells were stained for flow cytometric analysis of CD8+ T cells. The cells were stained for the surface marker CD3, CD4 and CD8. After 30 min surface staining, the cells were permeabilized with 2% PFA (15 min) and treated with saponin to ensure that the cell surface stays permeable. After 30 min intracellular staining (IL-2, IFN-g and TNF-a) samples were washed and measured with FACS Gallios. The frequency of cytokine-expressing CD8+ T cells is reported.

FIG. 17: C57BL/6 mice were vaccinated intramuscularly (100 μL/mouse in total; 50 μL/thigh) on days 0 and 28 of the experiment with a target dose of 1×10⁴ of HK1-GPgB(dTM) and HK3-GPgB(dTM). Sera from individual animals were generated prior to each vaccine dose (days 0, 28) as well as four weeks (day 56) after the last (second) injection. All sera were tested for the level of GPgB-specific IgG antibodies by ELISA; ELISA data are expressed as geometric mean GPgB-specific IgG endpoint titer.

FIG. 18: C57BL/6 mice were vaccinated intramuscularly (100 μL/mouse in total; 50 μL/thigh) on days 0 and 28 of the experiment with a target dose of 1×10⁴ of HK1-HgB(dTM) and HK3-HgB(dTM). Sera from individual animals were generated prior to each vaccine dose (days 0, 28) as well as four weeks (day 56) after the last (second) injection. All sera were tested for the level of HgB-specific IgG antibodies by ELISA; ELISA data are expressed as geometric mean HgB-specific IgG endpoint titer.

FIG. 19: HEK 293T cells were seeded in M6 well culture wells at a density of 500,000 cells per well. The next day, cells were infected with different LCMV strains at a multiplicity of infection of 0.05. Supernatant was harvested at the indicated time points and viral titres were determined by immunofocus assay. Symbols represent the mean of two wells.

FIG. 20: Groups of 5 New Zealand white rabbits were immunized intramuscularly with different doses (2.0×10², 4.4×10⁴ and 4.5×10⁶ FFU/dose) of HK1-HgB(dCt) on days 0 and 28. Sera were collected on days 0, 28 and 42 and anti-HCMVgB IgG antibody titers were measured by ELISA. Endpoint GMTs are shown.

FIG. 21A: C57BL/6 mice were immunized intramuscularly with 1×10⁵ FFU/dose of HK1-HgB(H3-2), HK1-HgB(VSVG-1) and recombinant gB/adjuvant on days 0, 21 and 42. Sera of immunized mice were collected on days 21, 42, 63, 91, 119, 147 and 175 and anti-HCMVgB IgG antibody titers were measured by ELISA. Endpoint GMTs are shown.

FIG. 21B: C57BL/6 mice were immunized intramuscularly with 1×10⁵ FFU/dose of HK1-HgB(H3-2), HK1-HgB(VSVG-1), HK1-HgB(dTM), HK1-HgB(dCt) and recombinant gB/adjuvant on days 0, 21 and 105. Sera of immunized mice were collected on days 21, 42, 63, 84, 105 and 126 and anti-HCMVgB IgG antibody titers were measured by ELISA. Endpoint GMTs are shown.

FIG. 22: Groups of 10 C57BL/6 mice were immunized intramuscularly with 9×10⁴ FFU/dose of HK1-HgB(dCt) alone or 9×10⁴ FFU/dose of HK1-Hpp65 alone or with 9×10⁴ FFU/dose of each HK1-HgB(dCt) and HK1-Hpp65 together on days 0 and 28. (A) Sera of immunized mice were collected on day 49 and anti-HCMVgB IgG antibody titers were measured by ELISA. (B) For the determination of T cell responses cytokines were analysed by flow cytometry. On day 49 after immunization, mice were sacrificed and single cell suspension of spleen cells were restimulated with a pool of peptides generated based on Shedlock D. et al (Human Vaccines & Immunotherapeutics 2012; 8:11, 1-14). Control cells were stimulated with medium only. After incubation with medium (lanes 1 and 2) or with specific peptides (lanes 3 and 4) cells were stained for flow cytometric analysis of CD8+ T cells. Expression of IL-2, IFN-g and TNF was analyzed

FIG. 23: Hartley guinea pigs (11 animals/group) were immunized intramuscularly three times (on days 0, 21 and 42) with 1.54×10⁶FFU/dose of either HK1-GPgB-dTM or HK1-GPpp65 in advance of breeding. Control animals (10/group) received buffer instead of rLCMV vector constructs. Animals were bred on day 63+ of the experiment. ˜45 days after gestation guinea pigs were challenged subcutaneously with 1×10⁵ pfu of guinea pig CMV. Pup mortality was measured at parturition and protection rates were determined by comparison of treatment groups for viremia and rates of pup death, * indicates significant (p<0.05) reduction.

FIG. 24: IFN α/β and γ receptors deficient AG129 mice (A) as well as T and B cell deficient RAG−/− mice were inoculated intracerebrally with 7.65×10⁵ as well as 7.65×10³ FFU/dose of either HK3-Hpp65 or the mouse analogue HK3-Mpp65 on day 0. Control groups of mice received either 100 FFU/dose of wildtype LCMV or diluent only. Mice were subsequently monitored for signs of illness and brain tissue were collected on the indicated days and analyzed for the presence of infectious virus.

FIG. 25: Hartley guinea pigs (18 animals/group) were immunized intramuscularly with 8×10⁵ FFU/dose of HK1-GPgB(dCt) (group 1), 8×10⁵ FFU/dose of HK1-GPpp65 (group 2), or 8×10⁵ FFU/dose of each HK1-GPgB(dCt) and HK1-GPpp65 (group 3) on days 0, 31 and 72 (group 1)/days 0, 31 and 70 (group 2)/days 0, 34 and 70 (group 3) of the experiment. In addition, Hartley guinea pigs (18 animals/group) were immunized subcutaneously with 50 μg of subunit gB protein, formulated in Complete Freund's Adjuvant (group 4) on days 0, 46 and 76. Sera of immunized animals were collected on days 0, 28, 52, 103 and 155 of the experiment and anti-gB antibody titers were analyzed by GPgB-specific IgG ELISA using a sera pool with assigned anti-gB antibody titer as a reference standard.

FIG. 26: Hartley guinea pigs (18 animals/group) were immunized intramuscularly with 8×10⁵ FFU/dose of HK1-GPgB(dCt) (group 1), 8×10⁵ FFU/dose of HK1-GPpp65 (group 2), or 8×10⁵ FFU/dose of each HK1-GPgB(dCt) and HK1-GPpp65 (group 3) on days 0, 31 and 72 (group 1)/days 0, 31 and 70 (group 2)/days 0, 34 and 70 (group 3). In addition, Hartley guinea pigs (18 animals/group) were immunized subcutaneously with 50 μg of subunit gB protein, formulated in Complete Freund's Adjuvant (group 4) on days 0, 46 and 76. Sera of immunized animals were collected on day 103 and the neutralizing activity of the sera of the experiment was analyzed. Dotted line indicates limit of detection. Sera samples that failed to reach the limit of detection in the assay were arbitrarily assigned a value of 20 for graphing and statistical calculations.

FIG. 27: Splenocytes were isolated from Hartley guinea pigs immunized intramuscularly with 8×10⁵ FFU/dose of HK1-GFP (group 1), 8×10⁵ FFU/dose of HK1-GPpp65 (group 2) or 8×10⁵ FFU/dose of each HK1-GPgB(dCt) and HK1-GPpp65 (group 3) and analyzed by ELISPOT assay. Three animals from each vaccine group were sacrificed after 2 doses of vaccine and three additional animals from each vaccine group were sacrificed after 3 vaccine doses. The magnitude of the pp65-specific splenocyte response for each animal was calculated using Prism6 as the “area under the curve” above the DMSO control of each animal's response to all pp65 peptide pools. (A) Average number of spots per animal is represented by data points for either 2 doses (circles) or 3 doses (boxes) of vaccine (Bars represent group mean and ±SEM). (B) Average number of spots per animal is represented by data points for HK1-GFP (circles), HK1-GPpp65 (squares), or HK1-GPgB(dCt)/HK1-GPpp65 (triangles) vaccinated animals (Bars represent group mean and ±SEM). P-values shown on figure were calculated using a Mann-Whitney U-test (Wilcoxon, Biometrics Bulletin, 1945, 1: 80-83; Mann & Whitney, Annals of mathematical Statistics, 1947, 18: 50-60).

FIG. 28: Hartley guinea pigs were immunized intramuscularly three times with 8×10⁵ FFU/dose of either HK1-GFP (group1), HK1-GPgB(dCt) (group 2), HK1-GPpp65 (group 3) or 8×10⁵ FFU/dose of each HK1-GPgB(dCt) and HK1-GPpp65 in combination (group 4) in advance of breeding. About one month after the last vaccine dose animals were allowed to breed. Pregnancies in guinea pig dams were confirmed and monitored by palpatation. Pregnant dams were challenged in the third trimester of gestation with 10⁵ plaque-forming units of salivary gland passaged guinea pig CMV and were subsequently monitored until delivery. Pup mortality was measured at parturition and protection rates were determined by comparison of treatment groups for rates of pup mortality.

6. DETAILED DESCRIPTION OF THE INVENTION

Provided herein are methods and compositions for the treatment or prevention of infection of a subject with CMV, or of reactivation of CMV in a subject. More specifically, provided herein are infectious, replication-deficient arenaviruses that comprise a nucleotide sequence encoding a CMV antigen. These viruses can be administered to a subject for the treatment or prevention of CMV infection or reactivation. The generation of infectious, replication-deficient arenavirus vectors for use with the present invention is described in more detail in Section 6.3.

Provided herein is a genetically modified arenavirus, where the arenavirus:

-   -   is infectious;     -   cannot form infectious progeny virus in a non-complementary cell         (i.e., a cell that does not express the functionality that is         missing from the replication-deficient arenavirus and causes it         to be replication-deficient);     -   is capable of replicating its genome and expressing its genetic         information; and     -   encodes a CMV antigen or a fragment thereof.

A genetically modified arenavirus described herein is infectious, i.e., it can attach to a host cell and release its genetic material into the host cell. A genetically modified arenavirus described herein is replication-deficient, i.e., the arenavirus is unable to produce further infectious progeny particles in a non-complementing cell. In particular, the genome of the arenavirus is modified (e.g., by deletion or functional inactivation of an ORF) such that a virus carrying the modified genome can no longer produce infectious progeny viruses. A non-complementing cell is a cell that does not provide the functionality that has been eliminated from the replication-deficient arenavirus by modification of the virus genome (e.g., if the ORF encoding the GP protein is deleted or functionally inactivated, a non-complementing cell does not provide the GP protein). However, a genetically modified arenavirus provided herein is capable of producing infectious progeny viruses in complementing cells. Complementing cells are cells that provide (in trans) the functionality that has been eliminated from the replication-deficient arenavirus by modification of the virus genome (e.g., if the ORF encoding the GP protein is deleted or functionally inactivated, a complementing cell does provide the GP protein). Expression of the complementing functionality (e.g., the GP protein) can be accomplished by any method known to the skilled artisan (e.g., transient or stable expression). A genetically modified arenavirus described herein can amplify and express its genetic information in a cell that has been infected by the virus. A genetically modified arenavirus provided herein comprises a nucleotide sequence that encodes a CMV antigen such as but not limited to the CMV antigens described in Section 6.2.

In certain embodiments, provided herein is a genetically modified arenavirus in which an ORF (ORF) of the arenavirus genome is deleted or functionally inactivated such that the resulting virus cannot produce further infectious progeny virus particles in non-complementing cells. An arenavirus particle comprising a genetically modified genome in which an ORF deleted or functionally inactivated can be produced in complementing cells (i.e., in cells that express the arenaviral ORF that has been deleted or functionally inactivated) (see Section 6.3). The genetic material of the resulting arenavirus particles can be transferred upon infection of a host cell into the host cell, wherein the genetic material can be expressed and amplified. In addition, the genome of the genetically modified arenavirus particles provided herein encodes a CMV antigen that can be expressed in the host cell.

In certain embodiments, the ORF that encodes the glycoprotein (GP) gene of the arenavirus is deleted to generate a replication-deficient arenavirus for use with the present invention. In a specific embodiment, the replication-deficient arenavirus comprises a genomic segment comprising a nucleotide sequence encoding a CMV antigen. Thus, in certain embodiments, a genetically modified arenavirus particle provided herein comprises a genomic segment that a) has a deletion or functional inactivation of an ORF that is present in the wild type form of the genomic segment; and b) encodes (either in sense or antisense) a CMV antigen (see Section 6.3).

In certain embodiments, the antigen encoded by the nucleic acid that is inserted into the genome of replication-deficient arenavirus can encode, for example, a CMV antigen or combinations of CMV antigens including, but not limited to:

-   -   a. a nucleotide sequence encoding a CMV glycoprotein gB or an         antigenic fragment thereof;     -   b. a nucleotide sequence encoding a CMV tegument protein pp65 or         an antigenic fragment thereof;     -   c. a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   d. a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   e. a nucleotide sequence encoding a CMV UL128 protein or an         antigenic fragment thereof;     -   f. a nucleotide sequence encoding a CMV UL130 protein or an         antigenic fragment thereof;     -   g. a nucleotide sequence encoding a CMV UL131A protein or an         antigenic fragment thereof.

A detailed description of the antigens described herein is provided in Section 6.2.

In certain embodiments, the arenaviruses used according to the invention described herein can be Old World viruses, for example, Lymphocytic choriomeningitis virus (LCMV). More detailed description of the arenaviruses described herein is provided in Section 6.1.

Provided herein are nucleic acids encoding the genome of such replication-deficient arenaviruses. In certain aspects, an infectious, replication-deficient arenavirus particle comprises a genomic segment comprising a nucleotide sequence of SEQ ID NO: 1, SEQ ID NO: 4, SEQ ID NO: 7, SEQ ID NO: 10, SEQ ID NO: 13, SEQ ID NO: 16, SEQ ID NO: 19, SEQ ID NO: 22, SEQ ID NO: 25, SEQ ID NO: 28, SEQ ID NO: 34, SEQ ID NO: 37, SEQ ID NO: 40, SEQ ID NO: 44, or SEQ ID NO: 49, or SEQ ID NO: 50.

Provided herein is an expression plasmid that encodes one or more components required for the generation of a viral vector described herein. Specifically, provided herein is an expression vector that encodes an LCMV S segment wherein the ORF for the GP protein has been deleted from the S segment and has been replaced with the ORF of human CMV glycoprotein gB with a truncation of the carboxy-terminus (e.g., having the amino acid sequence of SEQ ID NO: 18 or an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 18).

Provided herein are kits comprising one or two of the vector plasmids described herein. In certain embodiments, provided herein is a kit that comprises a) an expression plasmid that encodes the S segment of an LCMV vector; b) an expression plasmid that encodes the L segment of an LCMV vector; and c) an expression plasmid that encodes the complementing functionality. In a specific embodiment, provided herein is a kit comprising a) an expression vector that encodes an LCMV S segment wherein the ORF for the GP protein has been deleted from the S segment and has been replaced with the ORF of human CMV glycoprotein gB with a truncation of the carboxy-terminus (e.g., having the amino acid sequence of SEQ ID NO: 18 or an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 18); b) an expression plasmid that encodes the L segment of an LCMV vector; and c) an expression plasmid that encodes the LCMV GP protein (or a cell line that expresses LCMV GP protein).

Also provided herein are cell lines, cultures and methods of culturing cells infected with nucleic acids, vectors, and compositions provided herein. More detailed description of the nucleic acids, vector systems and cell lines described herein is provided in Section 6.4.

The invention relates to such genetically modified replication-deficient arenaviruses suitable as vaccines and to methods of using such arenaviruses in vaccination and treatment or prevention of infections by CMV or reactivation of CMV. More detailed description of methods of using such arenaviruses described herein is provided in Section 6.5.

In certain embodiments, immunization with an infectious, replication-deficient arenavirus that expresses a CMV antigen or a fragment thereof, as described herein provides a long-lasting immune response. In certain embodiments, maximal antibody levels can be achieved after two immunizations. In another embodiment, a third immunization can be administered for a boosting effect. In more specific embodiments, provided herein are administration schedules using the infectious, replication-deficient arenavirus in a vaccination for the treatment and/or prevention of infections by CMV or reactivation of CMV. A more detailed description of administration schedules using an infectious, replication-deficient arenavirus as described herein is provided in Section 6.5.

In certain embodiments, administering to a seronegative subject an infectious, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof, as described herein induces a detectable antibody titer for a minimum of at least 4 weeks. In another embodiment, administering to a subject infected with a CMV infection an infectious, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof, as described herein increases the antibody titer by at least 100%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000%. In certain embodiments, primary antigen exposure elicits a functional, (neutralizing) and minimum antibody titer of at least 50%, at least 100%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000% of mean control sera from infection-immune human subjects. In more specific embodiments, the primary neutralizing geometric mean antibody titer increases up to a peak value of at least 1:50, at least 1:100, at least 1:200, or at least 1:1000 within at least 4 weeks post-immunization. In another embodiment, immunization with an infection, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof, as described herein produces high titers of antibodies that last for at least 4 weeks, at least 8 weeks, at least 12 weeks, at least 6 months, at least 12 months, at least 2 years, at least 3 years, at least 4 years, or at least 5 years post-immunization following a single administration of the vaccine.

In yet another embodiment, secondary antigen exposure increases the antibody titer by at least 100%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000%. In another embodiment, secondary antigen exposure elicits a functional, (neutralizing) and minimum antibody titer of at least 50%, at least 100%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000% of mean control sera from infection-immune human subjects. In more specific embodiments, the secondary neutralizing geometric mean antibody titer increases up to a peak value of at least 1:50, at least 1:100, at least 1:200, or at least 1:1000 within at least 4 weeks post-immunization. In another embodiment, a second immunization with an infection, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof, as described herein produces high titers of antibodies that last for at least 4 weeks, at least 8 weeks, at least 12 weeks, at least 6 months, at least 12 months, at least 2 years, at least 3 years, at least 4 years, or at least 5 years post-immunization.

In yet another embodiment, a third boosting immunization increases the antibody titer by at least 100%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000%. In another embodiment, the boosting immunization elicits a functional, (neutralizing) and minimum antibody titer of at least 50%, at least 100%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000% of mean control sera from infection-immune human subjects. In more specific embodiments, the third boosting immunization elicits a functional, (neutralizing), and minimum antibody titer of at least 50%, at least 100%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000% of mean control sera from infection-immune human subjects. In another embodiment, a third boosting immunization prolongs the antibody titer by at least 4 weeks, at least 8 weeks, at least 12 weeks, at least 6 months, at least 12 months, at least 2 years, at least 3 years, at least 4 years, or at least 5 years post-immunization

In certain emobodiments, the infectious replication-deficient arenavirus expressing a CMV antign or fragment thereof, elicits a T cell independent or T cell dependent response. In other embodiments, the infectious, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof, elicits a T cell response. In other embodiments, the infections, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof, as described herein elicits a T helper response. In another embodiment, the infectious, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof, as described herein elicits a Th1-orientated response or a Th2-orientated response.

In more specific embodiments, the Th1-orientated response is indicated by a predominance of IgG1 antibodies versus IgG2. In other embodiments the ratio of IgG1:IgG2 is greater than 1:1, greater than 2:1, greater than 3:1, or greater than 4:1. In another embodiment the infectious, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof, as described hereon is indicated by a predominance of IgG3 antibodies.

In some embodiments, the infectious, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof elicits a CD8+ T cell response. In other embodiments, the infectious, replication-deficient arenavirus expressing a CMV antigen or a fragment thereof elicits a regulatory T cell response. In more specific embodiments, the regulatory T cell response maintains immune tolerance. In another embodiment, the infectious, replication-deficinet arenavirus expressing a CMV antigen or a fragment there of elicits both CD4+ and CD8+ T cell responses.

In certain embodiments, the infectious, replication-deficient arenavirus expressing a CMV antigen or fragment thereof, as described herein elicits high titers of neutralizing antibodies. In another embodiment, the infectious replication-deficient arenavirus expressing a CMV antigen or fragment thereof, as described herein elicits high titers of neutralizing antibodies than expression of the protein complex components individually.

In other embodiments, two or more infections, replication-deficient arenavirus expressing a CMV antigen elicits high titers of neutralizing antibodies. In a more specific embodiment, two or more infections, replication-deficient arenavirus expressing a CMV antigen elicit higher titers of neutralizing antibodies than an infectious, replication-deficient arenavirus expressing one CMV antigen or fragment thereof.

In another embodiment, the infectious, replication-deficient arenavirus expressing two, three, four, five, or more CMV antigens elicits higher titers of neutralizing antibodies than an infectious replication-deficient arenavirus expressing one CMV antigen or fragment thereof.

6.1 Infectious, Replication-Deficient Arenavirus Vectors Expressing a CMV Antigen

Arenaviruses for use with the methods and compositions provided herein can be of Old World viruses, for example Lassa virus, Lymphocytic choriomeningitis virus (LCMV), Mobala virus, Mopeia virus, or Ippy virus, or New World viruses, for example Amapari virus, Flexal virus, Guanarito virus, Junin virus, Latino virus, Machupo virus, Oliveros virus, Parana virus, Pichinde virus, Pirital virus, Sabia virus, Tacaribe virus, Tamiami virus, Bear Canyon virus, or Whitewater Arroyo virus. The genetically modified arenavirus can be generated as described in Section 6.3.

The wild type arenavirus genome consists of a short (˜3.4 kb) and a large (˜7.2 kb) RNA segment. The short segment carries the ORFs encoding the nucleoprotein NP and glycoprotein GP genes. The large segment encodes the RNA-dependent RNA polymerase L and the matrix protein Z genes. Wild type arenaviruses can be rendered replication-deficient to generate vaccine vectors by substituting the glycoprotein gene for one or more CMV antigens, against which immune responses are to be induced.

Infectious, replication-deficient arenavirus vectors expressing a CMV antigen, or a combination of CMV antigens as described herein, can be used to immunize (in a preventive manner) or treat (in an immunotherapeutic manner) subjects against CMV infection or reactivation. In a specific embodiment, a combination of gB and pp65 is used.

Arenavirus disease and immunosuppression in wild type arenavirus infection are known to result from unchecked viral replication. By abolishing replication, i.e., the ability to produce infectious progeny virus particles, of arenavirus vectors by deleting from their genome, e.g., the Z gene which is required for particle release, or the GP gene which is required for infection of target cells, the total number of infected cells can be limited by the inoculum administered, e.g., to a vaccine recipient, or accidentally transmitted to personnel involved in medical or biotechnological applications, or to animals. Therefore, abolishing replication of arenavirus vectors prevents pathogenesis as a result of intentional or accidental transmission of vector particles. In this invention, one important aspect consists in exploiting the above necessity of abolishment of replication in a beneficial way for the purpose of expressing a CMV antigen. In certain embodiments, an arenavirus particle is rendered replication deficient by genetic modification of its genome. Such modifications to the genome can include:

-   -   deletion of an ORF (e.g., the ORF encoding the GP, NP, L, or Z         protein);     -   functional inactivation of an ORF (e.g., the ORF encoding the         GP, NP, L, or Z protein). For example, this can be achieved by         introducing a missense or a nonsense mutation;     -   change of the sequence of the ORF (e.g., the exchange of an SIP         cleavage site with the cleavage site of another protease);     -   mutagenesis of one of the 5′ or 3′ termini of one of the genomic         segments;     -   mutagenesis of an intergenic region (i.e., of the L or the S         genomic segment).

In certain embodiments, an infectious, replication-deficient arenavirus expressing a CMV antigen described herein is a Lymphocytic choriomeningitis virus (LCMV) wherein the S segment of the virus is modified by substituting the ORF encoding the GP protein with an ORF encoding a CMV antigen.

In certain embodiments, a wild type arenavirus vector genome (FIG. 1) can be designed to retain at least the essential regulatory elements on the 5′ and 3′ untranslated regions (UTRs) of both segments, and/or also the intergenic regions (IGRs). Without being bound by theory, the minimal transacting factors for gene expression in infected cells remain in the vector genome as ORFs that can be expressed, yet they can be placed differently in the genome and can be placed under control of a different promoter than naturally, or can be expressed from internal ribosome entry sites. In certain embodiments, the nucleic acid encoding a CMV antigen is transcribed from one of the endogenous arenavirus promoters (i.e., 5′ UTR, 3′ UTR of the S segment, 5′ UTR, 3′ UTR of the L segment). In other embodiments, the nucleic acid encoding a CMV antigen is expressed from a heterologous introduced promoter sequences that can be read by the viral RNA-dependent RNA polymerase, by cellular RNA polymerase I, RNA polymerase II or RNA polymerase III, such as duplications of viral promoter sequences that are naturally found in the viral UTRs, the 28S ribosomal RNA promoter, the beta-actin promoter or the 5S ribosomal RNA promoter, respectively. In certain embodiments ribonucleic acids coding for CMV antigens are transcribed and translated either by themselves or as read-through by fusion to arenavirus protein ORFs, and expression of proteins in the host cell may be enhanced by introducing in the viral transcript sequence at the appropriate place(s) one or more, e.g., two, three or four, internal ribosome entry sites.

In certain embodiments, the vector generated to encode one or more CMV antigens may be based on a specific strain of LCMV. Strains of LCMV include Clone 13, MP strain, Arm CA 1371, Arm E-250, WE, UBC, Traub, Pasteur, 810885, CH-5692, Marseille #12, HP65-2009, 200501927, 810362, 811316, 810316, 810366, 20112714, Douglas, GR01, SN05, CABN and their derivatives. In certain embodiments, the vector generated to encode one or more CMV antigens may be based on LCMV Clone 13. In other embodiments, the vector generated to encode one or more CMV antigens may be based on LCMV MP strain. The sequence of the S segment of LCMV Clone 13 is listed as SEQ ID NO: 32. In certain embodiments, the sequence of the S segment of LCMV Clone 13 is the sequence set forth in SEQ ID NO: 31. The sequence of the L segment of LCMV Clone 13 is listed as SEQ ID NO: 33. The sequence of the S segment of LCMV strain MP is listed as SEQ ID NO: 53. The sequence of the L segment of LCMV strain MP is listed as SEQ ID NO: 49.

In certain embodiments, described herein is an infectious, replication-deficient arenavirus particle comprising a nucleotide sequence or fragment thereof selected from SEQ ID NO: 49, SEQ ID NO: 53, or a combination thereof

In certain embodiments, described herein is infectious, replication-deficient arenavirus particle comprising a nucleotide sequence, or a combination of nucleotide sequences, selected from the group consisting of:

-   -   a nucleotide sequence encoding a cytomegalovirus glycoprotein gB         or an antigenic fragment thereof;     -   a nucleotide sequence encoding a cytomegalovirus tegument         protein pp65 or an antigenic fragment thereof;     -   a nucleotide sequence encoding a cytomegalovirus glycoprotein gH         or an antigenic fragment thereof;     -   a nucleotide sequence encoding a cytomegalovirus glycoprotein gL         or an antigenic fragment thereof;     -   a nucleotide sequence encoding a cytomegalovirus UL128 protein         or an antigenic fragment thereof;     -   a nucleotide sequence encoding a cytomegalovirus UL130 protein         or an antigenic fragment thereof; and     -   a nucleotide sequence encoding a cytomegalovirus UL131A protein         or an antigenic fragment thereof.

6.2 CMV Antigens

In certain embodiments, antigens for use with the methods and compositions described herein are CMV antigens.

In certain embodiments, the ORFs encoding two, three, four, or five or more CMV antigens described are transcribed as a single transcript. In certain embodiments, the ORFs encoding the CMV antigens on that transcript are separated by a nucleic acid encoding a self-cleaving peptide or a ribosome-skipping sequence. In certain embodiments, the self-cleaving peptide (or the ribosome-skipping sequence) can be obtained from a 2A protein from a member of the virus family Picornaviridae. In certain specific embodiments, the self-cleaving peptide is obtained from (or derived from) Porcine teschovirus-1 2A, Thoseaasignavirus 2A, Foot-and-mouth disease virus 2A peptide, or equine rhinitis A virus 2A peptide. In certain specific embodiments, the 2A peptide obtained from (or derived from) the porcine teschovirus-1 2A has the highest cleavage efficiency. In certain embodiments, the 2A peptide has a high cleavage efficiency in combination with the CMV antigens described herein upstream or downstream of the 2A peptide.

In certain embodiments, the ORFs encoding two, three, four, or five or more CMV antigens are separated by a ribosome-skipping sequence. In more specific embodiments, the ribosome-skipping sequence is a cis-acting hydrolase element sequence.

In certain embodiments, the ORFs encoding two, three, four, or five, or more CMV antigens are separated by a self-cleaving protease obtained from (or derived from) tobacco etch viruses (TEVs) of the Potyviridae family.

In certain embodiments, a Gly-Ser-Gly linker is inserted at the N-terminus and C-terminus of the 2A peptide. In more specific embodiments, the Gly-Ser-Gly linker is inserted at the N-terminus of the 2A peptide. In more specific embodiments, the Gly-Ser-Gly linker is inserted at the C-terminus of the 2A peptide. In certain embodiments, the Gly-Ser-Gly linker improves the efficiency of cleavage by the 2A peptide.

In certain embodiments, the ORFs encoding two, three, four, or five or more CMV antigens are separated by an internal ribosome entry site. In certain embodiments, the internal ribosome entry site functions under the control of an upstream promoter. In certain embodiments the internal ribosome entry site is obtained from (or derived from) the encephalomyocarditis virus.

In certain embodiments the ORFs encoding two, three, four, or five, or more CMV antigens are separated by a 2A peptide and a furin cleavage site. In certain embodiments, the 2A peptide is flanked by a furin cleavage site. In certain embodiments, the furin cleavage site is located between an ORF encoding a CMV antigen and the 2A peptide. In certain embodiments the furin cleavage site is added upstream of the 2A peptide. In certain embodiments the furin cleavage site is added downstream of the 2A peptide. In certain embodiments, the furin cleavage site is located in the vector with the ORFs encoding two, three, four, or five, or more CMV antigens, a self-cleaving peptide, and combinations thereof. In certain embodiments, the furin cleavage site consensus sequence is R-X-K-/R-R. In a more specific embodiment the furin cleavage site is cleaved by the furin protein in the trans golgi network. In another embodiment the furin cleavage site removes the 2A peptide sequence. In yet another embodiment the furin cleavage site removes the self-cleaving peptide sequence at the C-terminus. For example, see Fang et al., Molecular Therapy. 2007; 15(6):1153-1159.

The certain embodiments, the ORFs encoding two, three, four, or five, or more CMV antigens are separated by the 2A peptide and a tag. In certain embodiments, the tag is linked to the 2A peptide. In certain embodiments, the tag is located between the 2A peptide and the furin cleavage site. In certain embodiments the tag is located at the C-terminus or N-terminus of the downstream ORF encoding the CMV antigen. In certain embodiments the tag is located at the C-terminus or N-terminus of the upstream ORF encoding the CMV antigen. In certain embodiments the tag is located in the vector with the ORFs encoding two, three, four, or more CMV antigens, a 2A peptide, a furin cleavage site, or a combination thereof. In certain embodiments the tag is a peptide tag. In more specific embodiments the tag is a V5 amino acid tag.

In certain embodiments, the ORFs encoding two, three, four, or five or more CMV antigens are separated by the 2A peptide and a spacer sequence. In certain embodiments, the spacer sequence is located upstream of the 2A peptide. In certain embodiments, the spacer sequence is located between the ORFs encoding the CMV antigens. In certain embodiments, the spacer sequence is located between the upstream of the 2A peptide and the tag. In certain embodiments, the spacer sequence is located between the upstream 2A peptide and the downstream furin cleavage site. In certain embodiments the spacer sequence is located in the vector with the ORFs encoding CMV antigens, a self-cleaving peptide, a furin cleavage site, a tag or a combination thereof. In certain embodiments, the spacer sequence increases cleavage efficiency.

In certain embodiments, the ORFs encoding two, three, four, or five, or more CMV antigens are separated by a nucleotide sequence that encodes: a self-cleaving peptide, an amino acid sequence that leads to release of the upstream amino acid sequence by “ribosome skipping” or a sequence element leading to binding of the ribosome and translation of the downstream sequence such as “internal ribosome entry sites” (IRES).

In certain embodiments, any strain of human CMV or any clinical isolate of human CMV can be used with the present invention to obtain the antigens for generation of the arenaviral vectors described herein. Such CMV strains include AD-169, Merlin, C327A (GenBank M60929), C076A (GenBank M85228), and C194A (GenBank 60926). Other human CMV strains and human CMV antigenic sequences that can be used with the presently disclosed compositions and methods are listed in Meyer-Koenig et al. 1998, J Infect Dis 177:1162-1169; Shedlock et al. 2012, Human Vaccines & Immunotherapuetics 8:1-14; and Chou and Dennison 1991, J Infect Dis 163:1229-34. The sequences and strains listed in Meyer-Koenig et al. 1998, J Infect Dis 177:1162-1169; Shedlock et al. 2012, Human Vaccines & Immunotherapuetics 8:1-14; and Chou and Dennison 1991, J Infect Dis 163:1229-34 are incorporated herein by reference.

In certain embodiments, the CMV antigen can be a CMV antigen ortholog, eg., a mammalian (i.e., non-human primate, pig, dog, cat, or horse) CMV antigen.

(a) gB Antigens

In certain embodiments, the antigen is the CMV major envelope glycoprotein gB or a fragment thereof. In certain embodiments, the antigen is a fragment of at least at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700 or more amino acids of CMV major envelope glycoprotein gB. In certain embodiments, the transmembrane domain of gB has been deleted. In some embodiments, the cytoplasmic domain of gB has been deleted. In certain embodiments, the antigen is an antigenic fragment of gB. In certain embodiments, the cytoplasmic and transmembrane domains of the glycoprotein gB have been deleted.

In specific embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5 and AS-4. (See FIG. 2). In certain embodiments, the gB antigen comprises the antigenic sites AS-2, AS-5, AS-4, and AS-1. In certain embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5, AS-4, AS-1, and AS-3. In certain embodiments, the antigen comprises the gB transmembrane domain. In certain embodiments, the antigen comprises the gB cytoplasmic domain. In certain embodiments, the antigen comprises gB antigenic sites AS-2, AS-5, AS-4, and AS-1, as well as the gB transmembrane domain. In certain embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5, AS-4, AS-1, and AS-3, as well as the gB transmembrane domain. In certain embodiments, the antigen comprises the gB ectodomain.

In certain embodiments, the antigen is a fusion protein between CMV glycoprotein gB or a fragment thereof and a heterologous polypeptide. In certain embodiments, the antigen is at least 10, 20, 30, 40, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, or at least 900 amino acids long. In certain embodiments, one or more domains of gB has/have been substituted by one or more domains of a heterologous protein. In certain embodiments, the cytoplasmic domain of gB has been substituted with the cytoplasmic domain of a heterologous protein. In certain embodiments, the cytoplasmic domain and transmembrane domains of gB have been substituted by the cytoplasmic domain of a heterologous protein. In certain embodiments, the cytoplasmic and transmembrane domains of gB have been substituted by the cytoplasmic and transmembrane domains of a heterologous protein. In certain embodiments, the cytoplasmic domain of gB has been substituted by the cytoplasmic and transmembrane domains of a heterologous protein. In certain embodiments, the heterologous protein is a glycoprotein from an RNA virus. In certain embodiments, the heterologous protein is a glycoprotein from VSV. In specific embodiments, the heterologous protein is VSV-G. In more specific embodiments, the heterologous protein is the VSV-G protein of wildtype VSV. In other specific embodiments, the heterologous protein is the VSV-G protein of VSV strain AV1 or AV2. In other specific embodiments, the heterologous protein is the VSV-G protein of VSV Serotype Indiana. In other specific embodiments, the heterologous protein is the VSV-G protein of VSV strain MARM U, MARM M, MRr or MRb. In certain embodiments, the antigen is encoded by a nucleic acid sequence that is 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 20 or SEQ ID NO: 23. In certain embodiments, the antigen comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 21 or SEQ ID NO: 24.

In specific embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5 and AS-4 and a heterologous transmembrane and cytoplasmic region derived from VSV-G. In certain embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5, AS-4, and AS-1 and a heterologous transmembrane and cytoplasmic region derived from VSV-G. In certain embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5, AS-4, AS-1, and AS-3 and a heterologous transmembrane and cytoplasmic region derived from VSV-G. In certain embodiments, the antigen comprises the gB transmembrane domain and a heterologous transmembrane and cytoplasmic region derived from VSV-G. In certain embodiments, the antigen comprises the gB cytoplasmic domain and a heterologous transmembrane and cytoplasmic region derived from VSV-G. In certain embodiments, the antigen comprises gB antigenic sites AS-2, AS-5, AS-4, and AS-1, as well as the gB transmembrane domain and a heterologous transmembrane and cytoplasmic region derived from VSV-G. In certain embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5, AS-4, AS-1, and AS-3, as well as the gB transmembrane domain and a heterologous transmembrane and cytoplasmic region derived from VSV-G. In certain embodiments, the antigen comprises the gB ectodomain and a heterologous transmembrane and cytoplasmic region derived from VSV-G.

In certain embodiments, the antigen is a fusion protein between CMV glycoprotein gB or a fragment thereof and a heterologous polypeptide. In certain embodiments, the antigen is at least 10, 20, 30, 40, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, or at least 900 amino acids long. In certain embodiments, one or more domains of gB has/have been substituted by one or more domains of a heterologous protein. In certain embodiments, the heterologous protein is a glycoprotein of influenza virus. In specific embodiments, the heterologous protein is the hemagglutinin protein of influenza virus (Flu-HA). In more specific embodiments, the heterologous protein is the hemagglutinin protein of influenza A virus. In other specific embodiments, the heterologous protein is the hemagglutinin protein of influenza B virus. In other specific embodiments, the heterologous protein is the hemagglutinin protein of influenza C virus. In certain embodiments, the antigen is encoded by a nucleic acid sequence that is 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 26 or SEQ ID NO: 29. In certain embodiments, the antigen comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 27 or SEQ ID NO: 30.

In specific embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5 and AS-4 and a heterologous transmembrane and cytoplasmic region derived from Flu-HA. In certain embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5, AS-4, and AS-1 and a heterologous transmembrane and cytoplasmic region derived from Flu-HA. In certain embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5, AS-4, AS-1, and AS-3 and a heterologous transmembrane and cytoplasmic region derived from Flu-HA. In certain embodiments, the antigen comprises the gB transmembrane domain and a heterologous transmembrane and cytoplasmic region derived from Flu-HA. In certain embodiments, the antigen comprises the gB cytoplasmic domain and a heterologous transmembrane and cytoplasmic region derived from Flu-HA. In certain embodiments, the antigen comprises gB antigenic sites AS-2, AS-5, AS-4, and AS-1, as well as the gB transmembrane domain and a heterologous transmembrane and cytoplasmic region derived from Flu-HA. In certain embodiments, the antigen comprises the gB antigenic sites AS-2, AS-5, AS-4, AS-1, and AS-3, as well as the gB transmembrane domain and a heterologous transmembrane and cytoplasmic region derived from Flu-HA. In certain embodiments, the antigen comprises the gB ectodomain and a heterologous transmembrane and cytoplasmic region derived from Flu-HA.

In certain embodiments, the gB protein is from CMV strain Merlin. Illustrative sequences that can be used with the viral vector compositions and uses thereof as decribed herein are set forth in SEQ ID NO: 58 to 63. In certain embodiments, the antigen comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 60 or SEQ ID NO: 63.

(b) Truncated gB Antigens

In certain embodiments, the carboxy terminus of the gB protein is truncated. In certain embodiments, the truncation of the carboxy terminus of the gB protein can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 29, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, or 134 amino acids long. In another embodiment, the truncation of the carboxy terminus of the gB protein can be 1-10, 10-20, 25-30, 30-40, 40-50, 50-60, 60-70, 70-80, 80-90, 90-100, 100-110, 110-120, 120-130, or 120-134 amino acids long. In other embodiments, the truncation of the carboxy terminus of the gB protein can be 10-134, 20-134, 30-134, 40-134, 50-134, 60-134, 70-134, 80-134, 90-134, 100-134, 110-134, or 120-134 amino acids long.

In certain embodiments, the gB protein with a truncation of the carboxy-terminus comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO: 3 over the entire length of the truncated gB protein. In more specific embodiments, the gB protein has a truncation between amino acids 772 to 906, and comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 3 over the entire length of the truncated gB protein. In other embodiments, the gB protein with a truncation of the carboxy-terminus comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to SEQ ID NO: 18.

In certain embodiments, the gB protein has a deletion in the carboxy-terminus. In certain embodiments the deletion in the carboxy-terminus can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 29, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, or 133 amino acids long. In another embodiment, the deletion in the carboxy terminus of the gB protein can be 1-10, 10-20, 20-30, 30-40, 40-50, 50-60, 60-70, 70-80, 80-90, 90-100, 100-110, 110-120, 120-130, or 130-133 amino acids long. In other embodiments, the deletion in the carboxy terminus of the gB protein can be 10-133, 20-133, 30-133, 40-133, 50-133, 60-133, 70-133, 80-133, 90-133, 100-133, 110-133, or 120-133 amino acids long.

In other embodiments, the gB protein with a truncation of the carboxy-terminus is still anchored in the membrane of the CMV viron.

(c) Pp65 Antigens

In certain embodiments, the antigen is the CMV tegument protein pp65 or a fragment thereof. In certain embodiments, the antigen is a fragment of at least at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500 or more amino acids of the CMV tegument protein pp65 or a fragment thereof. In certain embodiments, the antigen is an antigenic fragment of pp65. In certain embodiments, the antigen is encoded by a nucleic acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 35. In certain embodiments, the antigen comprises an amino acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 36.

(d) Pentameric Complex Antigens

In certain embodiments, the antigen is the CMV glycoprotein gH or a fragment thereof. In certain embodiments, the antigen is a fragment of at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700 or more amino acids of CMV glycoprotein gH or a fragment thereof. In certain embodiments, gH is lacking a transmembrane domain. In certain embodiments, the antigen contains only the gH ectodomain. In certain embodiments, the antigen is an antigenic fragment of gH. In certain embodiments, the antigen is encoded by a nucleic acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 38. In certain embodiments, the antigen is encoded by a nucleic acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 51.

In certain embodiments, the antigen is a derivative of the glycoprotein gH fragment. In certain embodiments the antigen is an antigenic fragment of gH with the C-terminal membrane anchor sequence deleted, gH(dTM).

In certain embodiments, the antigen is the CMV glycoprotein gL or a fragment thereof. In certain embodiments, the antigen is a fragment of at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250 or more amino acids of CMV glycoprotein gL or a fragment thereof. In certain embodiments, the antigen is an antigenic fragment of gL. In certain embodiments, the antigen is encoded by a nucleic acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 40.

In certain embodiments, the antigen is a pentameric complex protein or a fragment thereof. In certain embodiments, the antigen is a fragment of at least at least 10, 15, 20, 25, 50, 75, 100, 150 or more amino acids of a gene product of a gene of a pentameric complex protein of CMV or a fragment thereof. In certain more specific embodiments, the pentameric complex protein is CMV UL128 or a fragment thereof. In certain embodiments, the antigen is an antigenic fragment of UL128. In certain more specific embodiments, the pentameric complex protein is CMV UL130 or a fragment thereof. In certain embodiments, the antigen is an antigenic fragment of UL130. In certain more specific embodiments, the pentameric complex protein is CMV UL131A or a fragment thereof. In certain embodiments, the antigen is an antigenic fragment of UL131A. In certain embodiments, the antigen is encoded by a nucleic acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 42. In certain embodiments, the antigen is encoded by a nucleic acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 45. In certain embodiments, the antigen is encoded by a nucleic acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 47.

Nucleic acid sequences encoding a CMV antigen can be introduced in the genome of an infectious, replication-deficient arenavirus by substitution of the nucleic acid sequence of the ORF (ORF) of glycoprotein GP, the matrix protein Z, the nucleoprotein NP, or the polymerase protein L. In other embodiments, the nucleic acid sequence encoding the CMV antigen is fused to the ORF (ORF) of glycoprotein GP, the matrix protein Z, the nucleoprotein NP, or the polymerase protein L. The nucleotide sequence encoding the CMV antigen, once inserted into the genome of an infectious, replication-deficient arenavirus, can be transcribed and/or expressed under control of the four arenavirus promoters (5′ UTR and 3′ UTR of the S segment, and 5′ UTR and 3′ UTR of the L segment), as well as ribonucleic acids that can be inserted with regulatory elements that can be read by the viral RNA-dependent RNA polymerase, cellular RNA polymerase I, RNA polymerase II or RNA polymerase III, such as duplications of viral promoter sequences that are naturally found in the viral UTRs, the 28S ribosomal RNA promoter, the beta-actin promoter or the 5S ribosomal RNA promoter, respectively. The nucleic acids encoding the CMV antigen can be transcribed and/or expressed either by themselves or as read-through by fusion to arenavirus ORFs and genes, respectively, and/or in combination with one or more, e.g., two, three or four, internal ribosome entry sites.

In one embodiment, the antigen is one that is useful for the prevention of infectious disease. In a specific embodiment, the antigen is derived from CMV. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding gH or gL. In more specific embodiments, the nucleic acid sequence encoding the gH and gL are separated by a nucleic acid sequence encoding a 2A peptide. In other embodiments, the nucleic acid sequence encoding the gH and gL are separated by a nucleic acid sequence encoding a 2A peptide and a spacer. In more specific embodiments, the nucleic acid sequences encoding gH and gL are separated by a nucleic acid sequence encoding a 2A peptide and a furin cleavage site. In certain embodiments, the nucleic acid sequence encoding gH and gL are separated by a 2A peptide fused to a tag, such as, a V5 amino acid tag and a furin cleavage located upstream of the 2A peptide. In certain embodiments, the nucleic acid sequence encoding gH and gL is separated by a 2A peptide, a furin cleavage site fused to a tag, such as, a V5 amino acid tag, and a spacer. In specific embodiments the spacer is upstream of the 2A peptide. In yet more specific embodiments the spacer is upstream of the 2A peptide between the 2A peptide and the tag.

In certain embodiments, the nucleic acid sequences encoding glycoprotein gH (dTM) and glycoprotein gL are separated by a nucleic acid sequence encoding a self-cleaving peptide. In certain embodiments, the nucleic acid sequences that encode glycoprotein gH (dTM) and glycoprotein gL are separated by a 2A peptide. In certain embodiments the nucleic acid sequence encoding glycoprotein gH (dTM) and glycoprotein gL are connected by a 2A peptide that is fused to a tag, such as V5.

In certain embodiments, the nucleic acid sequences encoding two, three, four, or five or more CMV pentameric complex proteins are separated by a self-cleaving peptide. In certain embodiments, the nucleic acid sequences encoding CMV pentameric complex proteins are connected by a 2A peptide. In certain embodiments, nucleic acid sequences encoding CMV pentameric complex proteins are connected by a 2A peptide fused to a tag. In certain embodiments, nucleic acid sequences encoding CMV pentameric complex proteins are connected by a 2A peptide fused to a V5 amino acid tag.

In certain embodiments, the nucleic acid sequences encoding two, three, four, or five or more CMV pentameric complex proteins are separated by a self-cleaving peptide, an amino acid sequence that leads to release of upstream amino acid sequence by “ribosome skipping”, or a sequence element leading to binding of the ribosome and translation of the downstream sequence such as “internal ribosome entry sites” (IRES). In certain embodiments, the nucleic acid sequences encoding two, three, four, or five or more CMV pentameric complex proteins are separated by a self-cleaving peptide, an amino acid sequence that leads to release of upstream amino acid sequence by “ribosome skipping”, or a sequence element leading to binding of the ribosome and translation of the downstream sequence such as “internal ribosome entry sites” (IRES).

In certain embodiments, the nucleic acid sequences encoding two, three, four, or five or more CMV pentameric complex proteins are separated by a self-cleaving peptide and a furin cleavage site. In certain embodiments, the nucleic acid sequences encoding two, three, four, or five or more CMV pentameric complex proteins are separated by a self-cleaving peptide fused to a tag, such as, a V5 amino acid tag, and a furin cleavage site. In certain embodiments, the nucleic acid sequences encoding the CMV pentameric complex proteins are separated by a self-cleaving peptide fused to a tag, such as, a V5 amino acid tag, a furin cleavage site, and a spacer. In specific embodiments the spacer is upstream of the self-cleaving peptide.

(e) Substitution of the ORF Encoding the Glycoprotein of the Arenavirus

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding one, two, three, four, or five or more CMV antigens described herein. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding two, three, four, or five or more CMV antigens described herein, separated by self-cleaving peptides or ribosome-skipping sequences. In certain embodiments, the self-cleaving peptide (or the ribosome-skipping sequence) can be obtained from a 2A protein from a member of the virus family Picornaviridae. In certain specific embodiments, the self-cleaving peptide (or the ribosome-skipping sequence) is obtained from (or derived from) Porcine teschovirus-1 2A, Thoseaasignavirus 2A, or Foot-and-mouth disease virus 2A peptide.

In one embodiment, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding a CMV antigen. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigen that is a fragment of at least at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700 or more amino acids of a gene product of a gene of the major envelope glycoprotein gB of CMV or a fragment thereof. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigenic fragment of gB. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigens including, but not limited to the major envelope glycoprotein gB or a fragment of gB.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigen that is a fusion protein between gB and VSV-G. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigen that is at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500, 600, or at least 700 amino acids long. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 20 or SEQ ID NO: 23. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequence that encodes for an amino acid that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 21 or 24.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigen that is a fusion protein between gB and influenza virus hemagglutinin. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigen that is at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500, 600, or at least 700 amino acids long. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequence that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 26 or 29. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequence that encodes for an amino acid that is 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 90%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 27 or 30.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigen that is a fragment of at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500 or more amino acids of a gene product of a gene of the tegument protein pp65 of CMV or a fragment thereof. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigenic fragment of pp65. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigens including, but not limited to the pp65 or a fragment of pp65.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigen that is a fragment of at least at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700 or more amino acids of a gene product of a gene of the glycoprotein gH of CMV or a fragment thereof. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigenic fragment of gH. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigens including, but not limited to gH or a fragment of gH.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigen that is a fragment of at least at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250 or more amino acids of a gene product of a gene of the glycoprotein gL of CMV or a fragment thereof. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigenic fragment of gL. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigens including, but not limited to gL or a fragment of gL.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigen that is a fragment of at least at least 10, 15, 20, 25, 50, 75, 100, 150, 200, 250 or more amino acids of a gene product of a gene of the pentameric complex protein UL128 of CMV or a fragment thereof. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigenic fragment of UL128. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigens including, but not limited to UL128 or a fragment of UL128.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigen that is a fragment of at least at least 10, 15, 20, 25, 50, 75, 100, 150, 200 or more amino acids of a gene product of a gene of the pentameric complex protein UL130 of CMV or a fragment thereof. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigenic fragment of UL130. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigens including, but not limited to UL130 or a fragment of UL130.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigen that is a fragment of at least at least 10, 15, 20, 25, 50, 75, 100, 150 or more amino acids of a gene product of a gene of the pentameric complex protein UL131A of CMV or a fragment thereof. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding an antigenic fragment of UL131A. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by nucleic acid sequences encoding antigens including, but not limited to UL131A or a fragment of UL131A.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding two, three, four, or five pentameric complex proteins or fragments of at least 10, 15, 20, 25, 50, 75, 100, 150 or more amino acids thereof, separated by self-cleaving peptides or ribosome-skipping sequences or a sequence element leading to binding of the ribosome and translation of the downstream sequence such as IRES. In specific embodiments, the self-cleaving peptides or ribosome-skipping sequences are Teschovirus 2A (T2A) peptides.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding gH, gL, UL128, UL130, and UL131A. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding gH and gL. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding gH, gL, UL128, UL130, and UL131A, separated by a self-cleaving peptide or a ribosome-skipping sequence or a sequence element leading to binding of the ribosome and translation of the downstream sequence such as IRES. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding gH, gL, UL128, UL130, and UL131A, separated by T2A. In certain embodiments, the open reading frame that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding gH and gL by T2A.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding the ectodomain of gH, gL, UL128, UL130, and UL131A. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding the ectodomain of gH and gL. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding the ectodomain of gH, gL, UL128, UL130, and UL131A, separated by a self-cleaving peptide or a ribosme-skipping sequence or a sequence element leading to binding of the ribosome and translation of the downstream sequence such as IRES. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding gH and gL, separated by T2A. In certain embodiments the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding the ectodomain of gH and gL, separated by a T2A.

In certain other embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding two, three, four, five, six, or seven CMV antigens, fusion proteins of CMV antigens with heterologous sequences, or fragments of at least 10, 15, 20, 25, 50, 75, 100, 150 or more amino acids thereof, separated by self-cleaving peptides or ribosome-skipping sequences or a sequence element leading to binding of the ribosome and translation of the downstream sequence such as IRES. In specific embodiments, the self-cleaving peptides are Teschovirus 2A (T2A) peptides.

In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding one or more of gB or an antigenic fragment thereof, pp65 or an antigenic fragment thereof, gH or an antigenic fragment thereof, gL or an antigenic fragment thereof, UL128 or an antigenic fragment thereof, UL130 or an antigenic fragment thereof, and UL131A or an antigenic fragment thereof. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding one or more of gB or an antigenic fragment thereof, pp65 or an antigenic fragment thereof, gH or an antigenic fragment thereof, gL or an antigenic fragment thereof, UL128 or an antigenic fragment thereof, UL130 or an antigenic fragment thereof, and UL131A or an antigenic fragment thereof, separated by a self-cleaving peptide or a ribosome-skipping sequence or a sequence element leading to binding of the ribosome and translation of the downstream sequence such as IRES. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding one or more of gB or an antigenic fragment thereof, pp65 or an antigenic fragment thereof, gH or an antigenic fragment thereof, gL or an antigenic fragment thereof, UL128 or an antigenic fragment thereof, UL130 or an antigenic fragment thereof, and UL131A or an antigenic fragment thereof, separated by T2A. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding more than one copy of the CMV antigens herein. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding more than one copy of the CMV antigens herein, separated by a self-cleaving peptide or a ribosome-skipping sequence or a sequence element leading to binding of the ribosome and translation of the downstream sequence such as IRES. In certain embodiments, the ORF that encodes the glycoprotein of the arenavirus is substituted by a nucleic acid sequence encoding more than one copy of the CMV antigens herein, separated by T2A.

6.3 Generation of Infectious, Replication-Deficient Arenavirus Expressing a CMV Antigen

Generally, arenavirus particles can be recombinantly produced by standard reverse genetic techniques as described for LCMV (L. Flatz, A. Bergthaler, J. C. de la Torre, and D. D. Pinschewer, Proc Natl Acad Sci USA 103:4663-4668, 2006; A. B. Sanchez and J. C. de la Torre, Virology 350:370, 2006; E. Ortiz-Riano, B. Y. Cheng, J. C. de la Torre, L. Martinez-Sobrido. J Gen Virol. 94:1175-88, 2013). To generate infectious, replication-deficient arenaviruses for use with the present invention these techniques can be used, however, the genome of the rescued virus is modified as described in Section 6.1. These modifications can be: i) one or more, e.g., two, three or four, of the four arenavirus ORFs (glycoprotein (GP); nucleoprotein (NP); the matrix protein Z; the RNA-dependent RNA polymerase L) are removed or is functionally inactivated to prevent formation of infectious particles in normal cells albeit still allowing gene expression in arenavirus vector-infected host cells; and ii) nucleic acids coding for CMV antigens can be introduced. Infectious, replication-deficient viruses as described herein can be produced as described in International Patent Application Publication No. WO 2009/083210 (application number PCT/EP2008/010994), which is incorporated by reference herein in its entirety.

Once generated from cDNA, the infectious, replication-deficient arenaviruses provided herein can be propagated in complementing cells. Complementing cells are cells that provide the functionality that has been eliminated from the replication-deficient arenavirus by modification of its genome (e.g., if the ORF encoding the GP protein is deleted or functionally inactivated, a complementing cell does provide the GP protein).

Owing to the removal or functional inactivation of one or more of the viral genes in arenavirus vectors (here deletion of the glycoprotein, GP, will be taken as an example), arenavirus vectors can be generated and expanded in cells providing in trans the deleted viral gene(s), e.g., the GP in the present example. Such a complementing cell line, henceforth referred to as C-cells, is generated by transfecting a mammalian cell line such as BHK-21, HEK 293, VERO or other (here BHK-21 will be taken as an example) with one or more plasmid(s) for expression of the viral gene(s) of interest (complementation plasmid, referred to as C-plasmid). The C-plasmid(s) express the viral gene(s) deleted in the arenavirus vector to be generated under control of one or more expression cassettes suitable for expression in mammalian cells, e.g., a mammalian polymerase II promoter such as the CMV or EFlalpha promoter with a polyadenylation signal. In addition, the complementation plasmid features a mammalian selection marker, e.g., puromycin resistance, under control of an expression cassette suitable for gene expression in mammalian cells, e.g., polymerase II expression cassette as above, or the viral gene transcript(s) are followed by an internal ribosome entry site, such as the one of encephalomyocarditis virus, followed by the mammalian resistance marker. For production in E. coli, the plasmid additionally features a bacterial selection marker, such as an ampicillin resistance cassette.

Cells that can be used, e.g., BHK-21, HEK 293, MC57G or other, are kept in culture and are transfected with the complementation plasmid(s) using any of the commonly used strategies such as calcium-phosphate, liposome-based protocols or electroporation. A few days later the suitable selection agent, e.g., puromycin, is added in titrated concentrations. Surviving clones are isolated and subcloned following standard procedures, and high-expressing C-cell clones are identified using Western blot or flow cytometry procedures with antibodies directed against the viral protein(s) of interest. As an alternative to the use of stably transfected C-cells transient transfection of normal cells can complement the missing viral gene(s) in each of the steps where C-cells will be used below. In addition, a helper virus can be used to provide the missing functionality in trans.

Plasmids that can be used can be of two types: i) Two plasmids, referred to as TF-plasmids for expressing intracellularly in C-cells the minimal transacting factors of the arenavirus, is derived from e.g., NP and L proteins of LCMV in the present example; and ii) Plasmids, referred to as GS-plasmids, for expressing intracellularly in C-cells the arenavirus vector genome segments, e.g., the segments with designed modifications. TF-plasmids express the NP and L proteins of the respective arenavirus vector under control of an expression cassette suitable for protein expression in mammalian cells, typically e.g., a mammalian polymerase II promoter such as the CMV or EFlalpha promoter, either one of them preferentially in combination with a polyadenylation signal. GS-plasmids express the small (S) and the large (L) genome segments of the vector. Typically, polymerase I-driven expression cassettes or T7 bacteriophage RNA polymerase (T7-) driven expression cassettes can be used, the latter preferentially with a 3′-terminal ribozyme for processing of the primary transcript to yield the correct end. In the case of using a T7-based system, expression of T7 in C-cells must be provided by either including in the recovery process an additional expression plasmid, constructed analogously to TF-plasmids, providing T7, or C-cells are constructed to additionally express T7 in a stable manner. In certain embodiments, TF and GS plasmids can be the same, i.e. the genome sequence and transacting factors can be transcribed by T7, polI and polII promoters from one plasmid.

For recovering of the arenavirus vector, the following procedures can be used. First day: C-cells, typically 80% confluent in M6-well plates, are transfected with a mixture of the two TF-plasmids plus the two GS-plasmids. In certain embodiments, the TF and GS plasmids can be the same, i.e. the genome sequence and transacting factors can be transcribed by T7, polI and polII promoters from one plasmid. For this one can exploit any of the commonly used strategies such as calcium-phosphate, liposome-based protocols or electroporation.

3-5 days later: The culture supernatant (arenavirus vector preparation) is harvested, aliquoted and stored at 4° C., −20° C. or −80° C. depending on how long the arenavirus vector should be stored prior to use. Then the arenavirus vector preparation's infectious titer is assessed by an immunofocus assay on C-cells.

The invention furthermore relates to expression of a CMV antigen in a cell culture wherein the cell culture is infected with an infectious, replication-deficient arenavirus expressing a CMV antigen. When used for expression of a CMV antigen in cultured cells, the following two procedures can be used:

i) The cell type of interest is infected with the arenavirus vector preparation described herein at a multiplicity of infection (MOI) of one or more, e.g., two, three or four, resulting in production of the CMV antigen in all cells already shortly after infection.

ii) Alternatively, a lower MOI can be used and individual cell clones can be selected for their level of virally driven CMV antigen expression. Subsequently individual clones can be expanded infinitely owing to the non-cytolytic nature of arenavirus vectors. Irrespective of the approach, the CMV antigen can subsequently be collected (and purified) either from the culture supernatant or from the cells themselves, depending on the properties of the CMV antigen produced. However, the invention is not limited to these two strategies, and other ways of driving expression of CMV antigen using infectious, replication-deficient arenaviruses as vectors may be considered.

6.4 Nucleic Acids, Vector Systems and Cell Lines

In one embodiment, described herein is a nucleic acid sequence encoding the large genomic segment (L segment) of an infectious, replication-deficient arenavirus described herein, in which one ORF of the genomic segment is deleted or functionally inactivated, and the genomic segment comprises a nucleotide sequence encoding a CMV antigen.

In one embodiment, described herein is a nucleic acid sequence that encodes the short genomic segment (S segment) of an infectious, replication-deficient arenavirus described herein, in which one ORF of the genomic segment is deleted or functionally inactivated and wherein the short genomic segment comprises a nucleotide sequence encoding a CMV antigen. In another embodiment, described herein is a nucleic acid sequence that encodes the short genomic segment (S segment) of an infectious, replication-deficient arenavirus described herein, in which the ORF of the glycoprotein gene is deleted or functionally inactivated and wherein the short genomic segment comprises a nucleotide sequence encoding a CMV antigen. In certain, more specific embodiments, the CMV antigen is an antigen described in Section 6.2.

In certain embodiments, the nucleic acid sequences provided herein can be derived from a particular strain of LCMV. Strains of LCMV include Clone 13, MP strain, Arm CA 1371, Arm E-250, WE, UBC, Traub, Pasteur, 810885, CH-5692, Marseille #12, HP65-2009, 200501927, 810362, 811316, 810316, 810366, 20112714, Douglas, GR01, SN05, CABN and their derivatives. In specific embodiments, the nucleic acid is derived from LCMV Clone 13. In other specific embodiments, the nucleic acid is derived from LCMV MP strain.

In a more specific embodiment, provided herein is a nucleic acid encoding an arenavirus genomic segment comprising a sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, or 100% identical to the sequence of SEQ ID NO: 1, SEQ ID NO: 4, SEQ ID NO: 7, SEQ ID NO: 10, SEQ ID NO: 13, SEQ ID NO:16, SEQ ID NO: 19, SEQ ID NO: 22, SEQ ID NO: 25, OR SEQ ID NO: 28, SEQ ID NO: 34, SEQ ID NO: 37, SEQ ID NO: 44, or SEQ ID NO: 50. In another embodiment, provided herein is a nucleic acid that encodes an arenavirus genomic segment comprising (i) a nucleotide sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, or 100% identical to the sequence of nucleotide 1639 to 3315 of SEQ ID NO: 31; and (ii) a nucleotide sequence encoding a CMV antigen.

In another embodiment, provided herein is a nucleic acid that encodes an arenavirus genomic segment comprising (i) a nucleotide sequence encoding an expression product whose amino acid sequence is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, or 100% identical to the amino acid sequence encoded by 1639 to 3315 of SEQ ID NO: 31; and (ii) a nucleotide sequence encoding a CMV antigen.

In another embodiment, provided herein is a nucleic acid that encodes an arenavirus genomic segment comprising (i) a nucleotide sequence that is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, or 100% identical to the sequence of nucleotide 1640 to 3316 of SEQ ID NO: 32; and (ii) a nucleotide sequence encoding a CMV antigen.

In another embodiment, provided herein is a nucleic acid that encodes an arenavirus genomic segment comprising (i) a nucleotide sequence encoding an expression product whose amino acid sequence is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, or 100% identical to the amino acid sequence encoded by 1640 to 3316 of SEQ ID NO: 32; and (ii) a nucleotide sequence encoding a CMV antigen

In another embodiment, provided herein are nucleic acids that encode an arenavirus genomic segment comprising (i) a nucleotide sequence encoding at least one self-cleaving peptide (or ribosome-skipping sequence); and (ii) a nucleotide sequence encoding two, three, four, five, or more CMV antigens. In specific embodiments, the nucleotide sequence encoding a self-cleaving peptide encodes Teschovirus 2A. In certain embodiments, provided herein are nucleic acids that encode two, three, four, or five pentameric complex proteins separated by one or more nucleotide sequences encoding self-cleaving peptides (or ribosome-skipping sequences) (e.g., T2A). In certain other embodiments, provided herein are nucleic acids that encode one or more gB proteins or fragments thereof and one or more other CMV antigens, separated by one or more nucleotide sequences encoding self-cleaving peptides (or ribosome-skipping sequences). In other embodiments, provided herein are nucleic acids that encode one or more pp65 proteins or fragments thereof and one or more other CMV antigens, separated by one or more nucleotide sequences encoding self-cleaving peptides (or ribosome-skipping sequences). In specific embodiments, provided herein are nucleic acids that encode one or more pentameric proteins or fragments thereof and one or more other CMV antigens, separated by one or more nucleotide sequences encoding self-cleaving peptides (or ribosome-skipping sequences).

In one embodiment, described herein is a vector system comprising one or more vectors that together encode the genome of an infectious, replication-deficient arenavirus particle described herein. Specifically, provided herein is a vector system wherein the one or more vectors encode two arenavirus genomic segments, namely an L segment and an S segment, of an infectious, replication-deficient arenavirus described herein. Such a vector system can encode (on one or more separate DNA molecules):

An arenavirus S genomic segment that is modified such that an arenavirus particle carrying this modified S genomic segment cannot produce infectious progeny virus particles and an arenavirus L genomic segment that comprises a nucleotide sequence encoding (in sense or antisense) a CMV antigen;

An arenavirus L genomic segment that is modified such that an arenavirus particle carrying this modified L genomic segment cannot produce infectious progeny virus particles and an arenavirus S genomic segment that comprises a nucleotide sequence encoding (in sense or antisense) a CMV antigen;

An arenavirus S genomic segment that is modified such that an arenavirus particle carrying this modified S genomic segment cannot produce infectious progeny virus particles and wherein the arenavirus S genomic segment comprises a nucleotide sequence encoding (in sense or antisense) a CMV antigen and a wild type arenavirus L genomic segment; or

An arenavirus L genomic segment that is modified such that an arenavirus particle carrying this modified L genomic segment cannot produce infectious progeny virus particles and wherein the arenavirus L genomic segment comprises a nucleotide sequence encoding (in sense or antisense) a CMV antigen and a wild type arenavirus S genomic segment.

In certain embodiments, described herein is a nucleic acid sequence encoding an arenavirus (e.g., LCMV) genomic segment in which the ORF encoding the GP of the S genomic segment is substituted with a nucleotide sequence encoding:

a nucleotide sequence encoding a cytomegalovirus glycoprotein gB or an antigenic fragment thereof;

-   -   a nucleotide sequence encoding a cytomegalovirus tegument         protein pp65 or an antigenic fragment thereof;     -   a nucleotide sequence encoding a cytomegalovirus glycoprotein gH         or an antigenic fragment thereof;     -   a nucleotide sequence encoding a cytomegalovirus glycoprotein gL         or an antigenic fragment thereof;     -   a nucleotide sequence encoding a cytomegalovirus UL128 protein         or an antigenic fragment thereof;     -   a nucleotide sequence encoding a cytomegalovirus UL130 protein         or an antigenic fragment thereof; and     -   a nucleotide sequence encoding a cytomegalovirus UL131A protein         or an antigenic fragment thereof

In certain embodiments, described herein is a nucleic acid sequence encoding an arenavirus (e.g., LCMV) genomic segment in which the ORF encoding the GP of the S genomic segment is substituted with a nucleotide sequence encoding one or more CMV antigen sequences (e.g., one or more of those listed in the above paragraph), separated by nucleotide sequences encoding a self-cleaving peptide (or ribosome-skipping sequences). In specific embodiments, the nucleotide sequences encoding a self-cleaving peptide encode Teschovirus 2A.

In another embodiment, provided herein is a cell wherein the cell comprises a nucleic acid or a vector system described above in this section. Cell lines derived from such cells, cultures comprising such cells, and methods of culturing such cells infected are also provided herein. In certain embodiments, provided herein is a cell wherein the cell comprises a nucleic acid encoding the large genomic segment (L segment) of an infectious, replication-deficient arenavirus described herein, in which one ORF of the genomic segment is deleted or functionally inactivated, and the genomic segment comprises a nucleotide sequence encoding a CMV antigen.

In other embodiments, provided herein is a cell wherein the cell comprises a nucleic acid sequence that encodes the short genomic segment (S segment) of an infectious, replication-deficient arenavirus described herein, in which one ORF of the genomic segment is deleted or functionally inactivated and wherein the short genomic segment comprises a nucleotide sequence encoding CMV antigen gB or an antigenic fragment thereof.

In other embodiments, provided herein is a cell wherein the cell comprises a nucleic acid sequence that encodes the short genomic segment (S segment) of an infectious, replication-deficient arenavirus described herein, in which one ORF of the genomic segment is deleted or functionally inactivated and wherein the short genomic segment comprises a nucleotide sequence encoding a fusion protein comprising at least one domain from CMV antigen gB and a heterologous domain from VSV-G.

In other embodiments, provided herein is a cell wherein the cell comprises a nucleic acid sequence that encodes the short genomic segment (S segment) of an infectious, replication-deficient arenavirus described herein, in which one ORF of the genomic segment is deleted or functionally inactivated and wherein the short genomic segment comprises a nucleotide sequence encoding a fusion protein comprising at least one domain from CMV antigen gB and a heterologous domain from Flu-HA.

In other embodiments, provided herein is a cell wherein the cell comprises a nucleic acid sequence that encodes the short genomic segment (S segment) of an infectious, replication-deficient arenavirus described herein, in which one ORF of the genomic segment is deleted or functionally inactivated and wherein the short genomic segment comprises a nucleotide sequence encoding CMV antigen pp65 or an antigenic fragment thereof.

In other embodiments, provided herein is a cell wherein the cell comprises a nucleic acid sequence that encodes the short genomic segment (S segment) of an infectious, replication-deficient arenavirus described herein, in which one ORF of the genomic segment is deleted or functionally inactivated and wherein the short genomic segment comprises a nucleotide sequence encoding one or more of CMV antigens gH, gL, UL128, UL130, UL131A, or an antigenic fragments thereof. In specific embodiments, the genomic segment comprises a nucleotide sequence encoding one or more of the group of CMV antigens comprising gH, gL, UL128, UL130, UL131A, or antigenic fragments thereof, separated by one or more self-cleaving peptides (or ribosome-skipping sequences). In more specific embodiments, the one or more self-cleaving peptides are T2A peptides.

In other embodiments, provided herein is a cell wherein the cell comprises a nucleic acid sequence that encodes the short genomic segment (S segment) of an infectious, replication-deficient arenavirus described herein, in which one ORF of the genomic segment is deleted or functionally inactivated and wherein the short genomic segment comprises a nucleotide sequence encoding one or more of CMV antigens separated by one or more self-cleaving peptides (or ribosome-skipping sequences). In specific embodiments, the one or more self-cleaving peptides are T2A peptides.

In another embodiment, provided herein is a cell wherein the cell comprises two nucleic acids or a vector systems described herein. Cell lines derived from such cells, cultures comprising such cells, and methods of culturing such cells infected are also provided herein.

In certain embodiments, provided herein is a nucleic acid comprising a nucleotide sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 49 or SEQ ID NO: 53. In certain embodiments, provided herein is an expression vector comprising a nucleotide sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 49 or SEQ ID NO: 53. In certain embodiments, provided herein is a host cell comprising a nucleotide sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 49 or SEQ ID NO: 53.

In certain embodiments, provided herein is a nucleic acid comprising a nucleotide sequence encoding an amino acid sequence at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 54, 55, 56, or 57. In certain embodiments, provided herein is an expression vector comprising a nucleotide sequence encoding an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 54, 55, 56, or 57. In certain embodiments, provided herein is a host cell comprising a nucleotide sequence that encodes an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 54, 55, 56, or 57.

In certain embodiments, provided herein is an isolated protein comprising an amino acid sequence at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 54, 55, 56, or 57. In certain embodiments, provided herein is a host cell that expresses a protein comprising an amino acid sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 54, 55, 56, or 57. In certain embodiments, the host cell is cultured in cell culture medium.

In certain embodiments, provided herein is a nucleic acid comprising a nucleotide sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 32 or SEQ ID NO: 33. In certain embodiments, provided herein is an expression vector comprising a nucleotide sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 32 or SEQ ID NO: 33. In certain embodiments, provided herein is a host cell comprising a nucleotide sequence that is at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to SEQ ID NO: 32 or SEQ ID NO: 33.

6.5 Methods of Use

In one embodiment, provided herein are methods of treating an infection in a subject comprising administering to the subject one or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein or a composition thereof. In a specific embodiment, a method for treating an infection described herein comprises administering to a subject in need thereof an effective amount of one or more infectious, replication-deficient arenaviruses expressing a CMV antigen described herein or a composition thereof. The subject can be a mammal, such as but not limited to a human being, a mouse, a rat, a guinea pig, a domesticated animal, such as, but not limited to, a cow, a horse, a sheep, a pig, a goat, a cat, a dog, a hamster, a donkey. In a specific embodiment, the subject is a human.

In another embodiment, provided herein are methods for inducing an immune response against CMV in a subject comprising administering to the subject an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof.

In another embodiment, the subjects to whom an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered have, are susceptible to, or are at risk for a CMV infection or reactivation. In another specific embodiment, the subjects to whom an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered are infected with, are susceptible to, or are at risk for, an infection with CMV or reactivation with CMV.

In another embodiment, the subjects to whom an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered are suffering from, are susceptible to, or are at risk for, an infection with CMV in the pulmonary system, central nervous system, lymphatic system, gastrointestinal system, or circulatory system among others. In a specific embodiment, the subjects to whom an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered are suffering from, are susceptible to, or are at risk for, an infection with CMV in one or more organs of the body, including but not limited to the brain, liver, lungs, eyes, ears, intestines, esophagus, or salivary glands.

In another embodiment, the subjects to whom an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered to a subject suffering from symptoms including but not limited to fever, night sweats, tiredness, malaise, uneasiness, sore throat, swollen glands, joint pain, muscle pain, loss of appetite, weight loss, diarrhea, gastrointestinal ulcerations, gastrointestinal bleeding, shortness of breath, pneumonia, mouth ulcers, vision problems, hepatitis, jaundice, encephalitis, seizures, coma, or hearing loss.

In another embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein or a composition thereof is administered to a subject of any age group suffering from, are susceptible to, or are at risk for, an infection with CMV. In a specific embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein or a composition thereof is administered to a subject with a compromised immune system, a pregnant subject, a subject undergoing an organ or bone marrow transplant, a subject taking immunosuppressive drugs, a subject undergoing hemodialysis, a subject who has cancer, or a subject who is suffering from, are susceptible to, or are at risk for, an infection with CMV or reactivation of CMV. In a more specific embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein or a composition thereof is administered to a subject with a compromised immune system due to HIV infection, who is suffering from, is susceptible to, or is at risk for, an infection with CMV or reactivation of CMV. In yet another specific embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein or a composition thereof is administered to a subject who is a child of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 years of age suffering from, are susceptible to, or are at risk for, an infection with CMV or reactivation of CMV. In yet another specific embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered to a subject who is an infant suffering from, is susceptible to, or is at risk for, an infection with CMV or reactivation of CMV. In yet another specific embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered to a subject who is an infant of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 months of age suffering from, is susceptible to, or is at risk for, an infection with CMV or reactivation of CMV. In yet another specific embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered to an elderly subject who is suffering from, is susceptible to, or is at risk for, an infection with CMV or reactivation of CMV.

In another embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered to subjects with a heightened risk of disseminated CMV infection. In a specific embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered to subjects in neonatal period with immature neonatal immune system.

In another embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein or a composition thereof is administered to a subject having a dormant infection with CMV. In a specific embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered to a subject having a dormant infection with CMV, which can reactivate upon immune system compromise. Thus, provided herein is a method for preventing reactivation of CMV.

In another embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof is administered to subjects infected with one or more strains of CMV. In certain embodiments, one or more of those strains include AD169, Towne, Merlin, Toledo, FIX, PH, TR, Davis, TB40/E, 3157, 6397, 711, 5234, or other strains.

In another embodiment, administering an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein or a composition thereof to subjects confer cell-mediated immunity (CMI) against an infection with CMV or reactivation of CMV. Without being bound by theory, in another embodiment, an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein or a composition thereof infects and expresses antigens of interest in antigen presenting cells (APC) of the host (e.g., macrophages) for direct presentation of antigens on Major Histocompatibility Complex (MHC) class I and II. In another embodiment, administering an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein or a composition thereof to subjects induce plurifunctional IFN-γ and TNF-α co-producing CMV-specific CD4+ and CD8+ T cell responses (IFN-γ is produced by CD4+ and CD8+ T cells and TNF-α is produced by CD4+ T cells) of high magnitude to treat or prevent an infection with CMV or reactivation of CMV.

In another embodiment, administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof reduces the risk that an individual will develop an infection with CMV or reactivation of CMV by at least about 10%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, compared to the risk of developing an infection with CMV or reactivation of CMV in the absence of such treatment.

In another embodiment, administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof reduces the symptoms of an infection with CMV or reactivation of CMV by at least about 10%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, compared to the manifestation of the symptoms of an infection CMV or reactivation of CMV in the absence of such treatment.

In another embodiment, administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof in subjects with immature neonatal immune system induces cell-mediated immunity (CMI) response against an infection with CMV or reactivation of CMV by at least about 10%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, compared to cell-mediated immunity (CMI) response against an infection with CMV or reactivation of CMV in the absence of such a treatment.

In certain embodiments, administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof reduces the number of inclusion bodies detected in salivary glands or another histological sample. In certain embodiments, administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof reduces the number of anti-CMV antibodies detected in a patient blood sample. In certain embodiments, administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof reduces the amount of CMV pp65 detected in peripheral blood leukocytes via a CMV pp65 antigenemia test. In certain embodiments, administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof reduces the amount of CMV detected in urine, saliva, blood, tears, semen, or breast milk. In certain embodiments, administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof reduces the level of virus cultured from a urine, throat swab, bronchial lavage, or tissue sample. In certain embodiments, administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof reduces the level of virus detected through quantitative or qualitative PCR tests.

Changes in cell-mediated immunity (CMI) response function against an infection with CMV or reactivation of CMV induced by administering an infectious, replication-deficient arenavirus expressing a CMV antigen or a composition thereof in subjects can be measured by any assay known to the skilled artisan including, but not limited to flow cytometry (see, e.g., Perfetto S. P. et al., Nat Rev Immun. 2004; 4(8):648-55), lymphocyte proliferation assays (see, e.g., Bonilla F. A. et al., Ann Allergy Asthma Immunol. 2008; 101:101-4; and Hicks M. J. et al., Am J Clin Pathol. 1983; 80:159-63), assays to measure lymphocyte activation including determining changes in surface marker expression following activation of measurement of cytokines of T lymphocytes (see, e.g., Caruso A. et al., Cytometry. 1997; 27:71-6), ELISPOT assays (see, e.g., Czerkinsky C. C. et al., J Immunol Methods. 1983; 65:109-121; and Hutchings P. R. Et al., J Immunol Methods. 1989; 120:1-8), or Natural killer cell cytotoxicity assays (see, e.g., Bonilla F. A. et al., Ann Allergy Asthma Immunol. 2005 May; 94(5 Suppl 1):S1-63).

In another embodiment, described herein is a method of use with an infectious, replication-deficient arenavirus (e.g., LCMV) expressing a CMV antigen as described herein in which the ORF encoding the GP of the S genomic segment is substituted with a nucleotide sequence encoding:

-   -   a. a nucleotide sequence encoding a CMV glycoprotein gB or an         antigenic fragment thereof;     -   b. a nucleotide sequence encoding a CMV tegument protein pp65 or         an antigenic fragment thereof;     -   c. a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   d. a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   e. a nucleotide sequence encoding a CMV UL128 protein or an         antigenic fragment thereof;     -   f. a nucleotide sequence encoding a CMV UL130 protein or an         antigenic fragment thereof; or     -   g. a nucleotide sequence encoding a CMV UL131A protein or an         antigenic fragment thereof.

In another embodiment, provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a subject of child-bearing age an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein. See section 6.2. In specific embodiments, provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a seronegative subject of child-bearing age an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein. In yet another embodiment provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a subject of child-bearing age with the intention to procreate an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein.

In another embodiment, provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a subject of child-bearing age one or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein. See section 6.2. In specific embodiments, provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a seronegative subject of child-bearing age one or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein. In yet another embodiment, provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a subject of child-bearing age with the intention to procreate one or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein.

In another embodiment, provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a pregnant subject an infectious, replication-deficient arenavirus expressing a CMV antigen as described herein. In specific embodiments, provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a pregnant subject an effective amount of an infectious, replication-deficient arenavirus expressing a CMV antigen described herein.

In another embodiment, provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a pregnant subject one or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein. In specific embodiments, provided herein are methods of preventing transmission and/or infection of CMV from a mother to an unborn child comprising administering to a pregnant subject an effective amount of one or more infectious, replication-deficient arenaviruses expressing a CMV antigen described herein.

In another embodiment, administering an infectious, replication-deficient arenavirus expressing a CMV antigen reduces symptomatic congenital CMV infection. In another embodiment, administering an infectious, replication-deficient arenavirus expressing a CMV antigen reduces asymptomatic congenital CMV infection.

In another embodiment, administering one or more infectious, replication-deficient arenaviruses expressing a CMV antigen reduces symptomatic congenital CMV infection. In another embodiment, administering one or more infectious, replication-deficient arenaviruses expressing a CMV antigen reduces asymptomatic congenital CMV infection.

In another embodiment, administering an infectious, replication-deficient arenavirus expressing a CMV antigen reduces manifestations of congenital CMV infection by at least about 10%, at least about 20%, at least 25%, at least about 30%, at least about 35%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least 80%, at least 90%, or more. In another specific embodiment, administering an infectious, replication-deficient arenavirus expressing a CMV antigen reduces mortality of newborn infants with congenital CMV infection.

In another embodiment, administering one or more infectious, replication-deficient arenaviruses expressing a CMV antigen reduces manifestations of congenital CMV infection by at least about 10%, at least about 20%, at least 25%, at least about 30%, at least about 35%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least 80%, at least 90%, or more. In another specific embodiment, administering one or more infectious, replication-deficient arenaviruses expressing a CMV antigen reduces mortality of newborn infants with congenital CMV infection.

Such manifestations of congenital CMV include but are not limited to mental retardation, blindness and sensorineural deafness, microcephaly, chorioretinitis, intracranial calcifications, hepatosplenomegaly, hepatitis, jaundice, direct hyperbilirubinemia, thrombocytopenia, petechiae, oligohydramnios, polyhydramnios, prematurity, intrauterine growth retardation, nonimmune hydrops, fetal ascites, hyptonia, and anemia.

6.6 Compositions, Administration and Dosage

The invention furthermore relates to vaccines, immunogenic compositions, and pharmaceutical compositions comprising a genetically engineered arenavirus as described herein. Such vaccines and pharmaceutical compositions can be formulated according to standard procedures in the art.

In another embodiment, provided herein are compositions comprising an infectious, replication-deficient arenaviruses described herein. Such compositions can be used in methods of treatment and prevention of disease. In a specific embodiment, the compositions described herein are used in the treatment of subjects infected with, or susceptible to, an infection with CMV or reactivation of CMV. In another specific embodiment, the immunogenic compositions provided herein can be used to induce an immune response in a host to whom the composition is administered. The immunogenic compositions described herein can be used as vaccines and can accordingly be formulated as pharmaceutical compositions. In a specific embodiment, the immunogenic compositions described herein are used in the prevention of infection of subjects (e.g., human subjects) by CMV or reactivation of CMV in subjects (e.g., human subjects).

In certain embodiments, provided herein are immunogenic compositions comprising an arenavirus vector (or a combination of different arenavirus vectors) as described herein. In certain embodiments, such an immunogenic composition further comprises a pharmaceutically acceptable excipient. In certain embodiments, such an immunogenic composition further comprises an adjuvant. The adjuvant for administration in combination with a composition described herein may be administered before, concomitantly with, or after administration of said composition. In some embodiments, the term “adjuvant” refers to a compound that when administered in conjunction with or as part of a composition described herein augments, enhances and/or boosts the immune response to a infectious, replication-deficient arenavirus particle, but when the compound is administered alone does not generate an immune response to the infectious, replication-deficient arenavirus particle. In some embodiments, the adjuvant generates an immune response to the infectious, replication-deficient arenavirus particle and does not produce an allergy or other adverse reaction. Adjuvants can enhance an immune response by several mechanisms including, e.g., lymphocyte recruitment, stimulation of B and/or T cells, and stimulation of macrophages. When a vaccine or immunogenic composition of the invention comprises adjuvants or is administered together with one or more adjuvants, the adjuvants that can be used include, but are not limited to, mineral salt adjuvants or mineral salt gel adjuvants, particulate adjuvants, microparticulate adjuvants, mucosal adjuvants, and immunostimulatory adjuvants. Examples of adjuvants include, but are not limited to, aluminum salts (alum) (such as aluminum hydroxide, aluminum phosphate, and aluminum sulfate), 3 De-O-acylated monophosphoryl lipid A (MPL) (see GB 2220211), MF59 (Novartis), AS03 (GlaxoSmithKline), AS04 (GlaxoSmithKline), polysorbate 80 (Tween 80; ICL Americas, Inc.), imidazopyridine compounds (see International Application No. PCT/US2007/064857, published as International Publication No. WO2007/109812), imidazoquinoxaline compounds (see International Application No. PCT/US2007/064858, published as International Publication No. WO2007/109813) and saponins, such as QS21 (see Kensil et al., in Vaccine Design: The Subunit and Adjuvant Approach (eds. Powell & Newman, Plenum Press, N Y, 1995); U.S. Pat. No. 5,057,540). In some embodiments, the adjuvant is Freund's adjuvant (complete or incomplete). Other adjuvants are oil in water emulsions (such as squalene or peanut oil), optionally in combination with immune stimulants, such as monophosphoryl lipid A (see Stoute et al., N. Engl. J. Med. 336, 86-91 (1997)).

The compositions comprise the infectious, replication-deficient arenaviruses described herein alone or together with a pharmaceutically acceptable carrier. Suspensions or dispersions of genetically engineered arenaviruses, especially isotonic aqueous suspensions or dispersions, can be used. The pharmaceutical compositions may be sterilized and/or may comprise excipients, e.g., preservatives, stabilizers, wetting agents and/or emulsifiers, solubilizers, salts for regulating osmotic pressure and/or buffers and are prepared in a manner known per se, for example by means of conventional dispersing and suspending processes. In certain embodiments, such dispersions or suspensions may comprise viscosity-regulating agents. The suspensions or dispersions are kept at temperatures around 2-8° C., or preferentially for longer storage may be frozen and then thawed shortly before use. For injection, the vaccine or immunogenic preparations may be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks's solution, Ringer's solution, or physiological saline buffer. The solution may contain formulatory agents such as suspending, stabilizing and/or dispersing agents.

In certain embodiments, the compositions described herein additionally comprise a preservative, e.g., the mercury derivative thimerosal. In a specific embodiment, the pharmaceutical compositions described herein comprise 0.001% to 0.01% thimerosal. In other embodiments, the pharmaceutical compositions described herein do not comprise a preservative.

The pharmaceutical compositions comprise from about 10³ to about 10¹¹ focus forming units of the genetically engineered arenaviruses. Unit dose forms for parenteral administration are, for example, ampoules or vials, e.g., vials containing from about 10³ to 10¹⁰ focus forming units or 10⁵ to 10¹⁵ physical particles of genetically engineered arenaviruses.

In another embodiment, a vaccine or immunogenic composition provided herein is administered to a subject by, including but not limited to, oral, intradermal, intramuscular, intraperitoneal, intravenous, topical, subcutaneous, percutaneous, intranasal and inhalation routes, and via scarification (scratching through the top layers of skin, e.g., using a bifurcated needle). Specifically, subcutaneous or intravenous routes can be used.

For administration intranasally or by inhalation, the preparation for use according to the present invention can be conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebulizer, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges of, e.g., gelatin for use in an inhaler or insufflators may be formulated containing a powder mix of the compound and asuitable powder base such as lactose or starch.

The dosage of the active ingredient depends upon the type of vaccination and upon the subject, and their age, weight, individual condition, the individual pharmacokinetic data, and the mode of administration.

The invention relates also to processes and to the use of genetically engineered arenaviruses for the manufacture of vaccines in the form of pharmaceutical preparations, which comprise genetically engineered arenaviruses as active ingredient. The pharmaceutical compositions of the present invention are prepared in a manner known per se, for example by means of conventional mixing and/or dispersing processes.

6.7 Optimized Generation of LCMV Vectors

Owing to the removal or functional inactivation of one or more of the viral genes in arenavirus vectors (here deletion of the glycoprotein, GP, will be taken as an example) arenavirus vectors can be generated and expanded in cells that provide the deleted or functionally inactivated viral gene(s) (e.g., the GP) “in trans.” The resulting virus itself is infectious but is unable to produce further infectious progeny particles in non-complementing cells due to the lack of the deleted or functionally inactivated viral gene(s) (e.g., the GP). The complementing cell can provide the missing functionality either by stable transfection, transient transfection, or by infection with a helper virus that expresses the missing functionality.

In certain embodiments, the complementing cell provides the viral gene that has been deleted or functionally inactivated from the arenavirus vector genome. In a specific embodiment, the complementing cell provides the viral gene from a viral strain that is the same as the viral strain that was used to generate the genome of the arenavirus vector. In another embodiment, the complementing cell provides the viral gene from a viral strain that is different from the viral strain that was used to generate the genome of the arenavirus vector. For example, the viral gene provided in the complementing cell is obtained from the MP strain of LCMV and encodes a protein having the amino acid sequence of SEQ ID NO: 54, 55, 56, or 57.

In a specific embodiment, the complementing cell provides the GP of the MP strain of LCMV and the arenavirus vector comprises an ORF of a human CMV antigen as described herein in place of the ORF encoding the GP protein. In an even more specific embodiment, the complementing cell provides the GP of the MP strain of LCMV and the arenavirus vector is obtained from LCMV Clone 13 and comprises an ORF of a human CMV antigen as described herein in place of the ORF encoding the GP protein. In an even more specific embodiment, the GP protein is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, at least 99%, or 100% identical to the amino acid sequence of SEQ ID NO: 55.

6.8 Combination Therapy

6.8 (a) Methods

In one embodiment, provided herein are methods of treating and/or preventing a CMV infection in a subject comprising administering to the subject two or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein. See, e.g., Section 6.2. In specific embodiments, a method for treating and/or preventing a CMV infection comprises administering a first infectious, replication-deficient arenavirus expressing a CMV antigen as described herein, e.g., in which the ORF encoding the GP of the S genomic segment is substituted with a nucleotide sequence encoding the CMV antigen, wherein the CMV antigen can be but is not limited to:

-   -   a) a nucleotide sequence encoding a CMV glycoprotein gB or an         antigenic fragment thereof;     -   b) a nucleotide sequence encoding a CMV tegument protein pp65 or         an antigenic fragment thereof;     -   c) a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   d) a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   e) a nucleotide sequence encoding a CMV glycoprotein UL128 or an         antigenic fragment thereof;     -   f) a nucleotide sequence encoding a CMV glycoprotein UL130 or an         antigenic fragment thereof;     -   g) a nucleotide sequence encoding a CMV glycoprotein UL131A or         an antigenic fragment thereof.         and a second infectious, replication-deficient arenavirus         expressing a CMV antigen as described herein, e.g., in which the         ORF encoding the GP of the S genomic segment is substituted with         a nucleotide sequence encoding the CMV antigen, wherein the CMV         antigen can be but is not limited to:     -   a) a nucleotide sequence encoding a CMV glycoprotein gB or an         antigenic fragment thereof;     -   b) a nucleotide sequence encoding a CMV tegument protein pp65 or         an antigenic fragment thereof;     -   c) a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   d) a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   e) a nucleotide sequence encoding a CMV glycoprotein UL128 or an         antigenic fragment thereof;     -   f) a nucleotide sequence encoding a CMV glycoprotein UL130 or an         antigenic fragment thereof;     -   g) a nucleotide sequence encoding a CMV glycoprotein UL131A or         an antigenic fragment thereof.

In specific embodiments, provided herein are methods for treating and/or preventing a CMV infection comprising administering a first infectious, replication-deficient arenavirus expressing a first CMV antigen, selected from: a CMV tegument protein pp65 or an antigenic fragment thereof; a CMV glycoprotein gH or an antigenic fragment thereof; a CMV glycoprotein gL; a CMV glycoprotein UL128 or an antigenic fragment thereof; or an antigenic fragment thereof; a CMV glycoprotein UL130 or an antigenic fragment thereof; or a CMV glycoprotein UL131A or an antigenic fragment thereof, as described herein and a second infectious, replication-deficient arenavirus expressing a second CMV antigen, selected from: a nucleotide sequence encoding a CMV glycoprotein gB or an antigenic fragment thereof; a CMV tegument protein pp65 or an antigenic fragment thereof; a CMV glycoprotein gH or an antigenic fragment thereof; a CMV glycoprotein gL; a CMV glycoprotein UL128 or an antigenic fragment thereof; or an antigenic fragment thereof; a CMV glycoprotein UL130 or an antigenic fragment thereof; or a CMV glycoprotein UL131A or an antigenic fragment thereof.

In certain embodiments, provided herein are methods for treating and/or preventing an infection comprising administering two arenavirus vector constructs expressing a CMV antigen as described herein. In a specific embodiment, the two arenavirus vector constructs express a different CMV antigen.

In certain embodiments, provided herein are methods for treating and/or preventing an infection comprising administering two or more arenavirus vector constructs expressing a CMV antigen as described herein. In a specific embodiment, provided herein are methods for treating and/or preventing an infection comprising administering three or more arenavirus vector constructs expressing a CMV antigen as described herein. In another embodiment, provided herein are methods for treating/and or preventing an infection comprising administering four or more arenavirus vector constructs, five or more arenavirus vector constructs, six or more arenavirus vector constructs or 7 arenavirus vector constructs each expressing a CMV antigen as described herein. In certain embodiments, the arenavirus vector construct can be LCMV.

In certain embodiments, provided herein are methods for treating and/or preventing an infection comprising administering two or more arenavirus vector constructs each expressing a different CMV antigen as described herein. In a specific embodiment, provided herein are methods for treating and/or preventing an infection comprising administering three or more arenavirus vector constructs, each expressing a different CMV antigen as described herein. In another embodiment, provided herein are methods for treating/and or preventing an infection comprising administering four or more arenavirus vector constructs, five or more arenavirus vector constructs, six or more arenavirus vector constructs, or 7 arenavirus vector constructs each expressing a different CMV antigen as described herein. In certain embodiments, the arenavirus vector construct can be LCMV.

In specific embodiments, the antigen is the CMV envelope glycoprotein gB or a fragment thereof (See, e.g., Section 6.2(a)). In more specific embodiments, the antigen is the CMV envelope glycoprotein gB with a truncation of the carboxy-terminus. (See, e.g., Section 6.2(b)).

In certain embodiments, the antigen is the CMV tegument protein pp65 or a fragment thereof. (See, e.g., Section 6.2(c)).

In certain embodiments, the antigen is a CMV pentameric complex protein. In another embodiment the CMV pentameric complex antigen is gH, gH (dTM), gL, UL128, UL131A, or UL130 or combinations thereof. (See, e.g., Section 6.2(d)).

In certain embodiments, the vector generated to encode one or more CMV antigens as described herein comprises one or more nucleic acids encoding a CMV antigen and combinations thereof as described. In specific embodiments the CMV antigens as described herein are separated by various linkers, spacers, and cleavage sites as described herein.

In another embodiment, the vector generated to encode one or more CMV antigens as described herein of the first infectious, replication-deficient arenavirus may be based on LCMV Clone 13 or LCMV MP strain. (See, e.g., Section 7.1).

In another embodiment, the vector generated to encode one or more CMV antigens as described herein of the second infectious, replication-deficient arenavirus may be based on LCMV Clone 13 or LCMV MP strain. (See, e.g., Section 7.1).

In a specific embodiment, provided herein are methods of treating and/or preventing an infection in a subject comprising administering to the subject a first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or an antigenic fragment thereof.

In a specific embodiment, provided herein are methods of treating and/or preventing an infection in a subject comprising administering sequentially to the subject a first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or an antigenic fragment thereof.

In a specific embodiment, provided herein are methods of treating and/or preventing an infection in a subject comprising administering simultaneously to the subject a first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or an antigenic fragment thereof.

In another embodiment, the first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof is a primary vaccine antigen and the second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or an antigenic fragment thereof is a secondary vaccine antigen.

In a specific embodiment, provided herein are methods of treating and/or preventing an infection with CMV in a subject comprising administering to the subject a first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus. (See, e.g., Section 6.2(b) for truncated gB proteins).

In a specific embodiment, provided herein are methods of treating and/or preventing an infection with CMV in a subject comprising administering sequentially to the subject a first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus. (See, e.g., Section 6.2(b) for truncated gB proteins).

In a specific embodiment, provided herein are methods of treating and/or preventing an infection with CMV in a subject comprising administering simultaneously to the subject a first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus. (See, e.g., Section 6.2(b) for truncated gB proteins).

In another embodiment, the first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof is a primary vaccine antigen and the second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus is a secondary vaccine antigen.

In certain embodiments, administering a first infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or a fragment thereof or a CMV tegument protein pp65 and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or a fragment thereof or a CMV tegument protein pp65 provides a better protective effect to CMV after vaccination than administering a single infectious, replication-deficient arenavirus expressing a CMV antigen, e.g., expressing only the glycoprotein gB (or a fragment thereof) or only the tegument protein pp65. In other embodiments, administering a first infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or a fragment thereof or a CMV tegument protein pp65 and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or a fragment thereof or a CMV tegument protein pp65 elicits a greater immune response than administering a single infectious, replication-deficient arenavirus expressing a CMV antigen e.g., expressing only the glycoprotein gB (or a fragment thereof) or only the tegument protein pp65. In another embodiment, administering a first infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or a fragment thereof or a CMV tegument protein pp65 and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or a fragment thereof, or a CMV tegument protein pp65 elicits a larger CD8+ T cell response than administering a single infectious, replication-deficient arenavirus expressing a CMV antigen e.g., expressing only the glycoprotein gB (or a fragment thereof) or only the tegument protein pp65. In other embodiments, administering a first infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or a fragment thereof or a CMV tegument protein pp65 and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or a fragment thereof or a CMV tegument protein pp65 elicits higher titers of neutralizing antibodies than administering a single infectious, replication-deficient arenavirus expressing a CMV antigen e.g., expressing only the glycoprotein gB (or a fragment thereof) or only the tegument protein pp65.

In certain embodiments, the infectious replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus (see Section 6.2(b)) provides a better protective effect to CMV after vaccination than an infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB, wherein the transmembrane domain of gB has been deleted, as tested by ELISA, neutralizing antibody assay, and animal models. See Section 6.9. In other embodiments, the infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus elicits a greater immune response than an infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB, wherein the transmembrane domain of gB has been deleted. In certain embodiments, the infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus elicits a larger CD8+ T cell response than the infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB, wherein the transmembrane domain of gB has been deleted. In other embodiments the replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus elicits higher titers of neutralizing antibodies than the infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB, wherein the transmembrane domain of gB has been deleted. (See e.g., FIGS. 12, 13 and 25, 26).

In yet another embodiment, provided herein is the combined use of the replication-deficient arenavirus expressing a CMV antigen described herein and one or more replication-defective virus vectors. In a more specific embodiment the replication-defective virus vector is selected from the group comprising of poxviruses, adenoviruses, alphaviruses, herpes simplex viruses, paramyxoviruses, rhabdoviruses, poliovirus, adeno-associated virus, and sendai virus, and mixtures thereof. In a specific embodiment, the poxvirus is a modified vaccine Ankara.

In yet another embodiment, provided herein is the combined use of the replication-deficient arenavirus expressing a CMV antigen described herein and one or more replication-defective virus vectors expressing a CMV antigen. In a more specific embodiment the replication-defective virus vector is selected from the group comprising of poxviruses, adenoviruses, alphaviruses, herpes simplex viruses, paramyxoviruses, rhabdoviruses, poliovirus, adeno-associated virus, and sendai virus, and mixtures thereof. In a specific embodiment, the poxvirus is a modified vaccine Ankara.

In another embodiment, the first infectious, replication-deficient arenavirus expressing a CMV antigen as described herein is administered before or after the second infectious, replication-deficient arenavirus expressing a CMV antigen as described herein. For example the first infectious, replication-deficient arenavirus expressing a CMV antigen is administered around 30-60 minutes before or after the first administration of the second infectious, replication-deficient arenavirus.

In another embodiment, the first infectious, replication-deficient arenavirus expressing a vaccine antigen is administered before the second infectious, replication-deficient arenavirus expressing a vaccine antigen. In certain embodiments there is a period of about 1 hour, 2 hours, 3 hours, 6 hours, 12 hours, 1 day, 2 days, 3 days, 5 days, 1 week, 2 weeks, 1 month, 2 months, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, 1 year between the administration of the first infectious, replication-deficient arenavirus and the second infectious, replication-deficient arenavirus.

In another embodiment, two infectious, replication-deficient arenaviruses are administered in a treatment regime at molar ratios ranging from about 1:1 to 1:1000, in particular including: 1:1 ratio, 1:2 ratio, 1:5 ratio, 1:10 ratio, 1:20 ratio, 1:50 ratio, 1:100 ratio, 1:200 ratio, 1:300 ratio, 1:400 ratio, 1:500 ratio, 1:600 ratio, 1:700 ratio, 1:800 ratio, 1:900 ratio, 1:1000 ratio.

In another embodiment, the subjects whom two or more infectious, replication-deficient arenavirus expressing a CMV antigen described herein is administered have, are susceptible to, or are at risk for a CMV infection or reactivation. In another embodiment, the subjects whom two or more infections, replication-deficient arenaviruses expressing a CMV antigen described herein is administered are infected with, are susceptible to, or are at risk for, an infection with CMV or reactivation with CMV.

In another embodiment, the subjects whom two or more infectious, replication-deficient arenaviruses expressing a CMV antigen described herein, are administered simultaneously have, are susceptible to, or are at risk for a CMV infection or reactivation. In another embodiment, the subjects whom two or more infections, replication-deficient arenaviruses expressing a CMV antigen described herein are administered simultaneously are infected with, are susceptible to, or are at risk for, an infection with CMV or reactivation with CMV.

In another embodiment, the subjects whom two or more infectious, replication-deficient arenaviruses expressing a CMV antigen described herein, are administered sequentially have, are susceptible to, or are at risk for a CMV infection or reactivation. In another embodiment, the subjects whom two or more infections, replication-deficient arenaviruses expressing a CMV antigen described herein are administered sequentially are infected with, are susceptible to, or are at risk for, an infection with CMV or reactivation with CMV.

In another embodiment, said two or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein are further administered in combination with at least one other medicament for treating and/or preventing CMV. Therapeutic medicaments for treating and/or preventing CMV include, but are not limited to Valganciclovir, Ganciclovir, Foscarnet, Cidofovir, or Maribavir.

In another embodiment, said two or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein are further administered in a combination with at least one other immunomodulator. In a more specific embodiment, said two or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein are further administered in a combination with at least one Th1-specific adjuvant. In a more specific embodiment the Th-1 specific adjuvant is Bacillus Calmette-Guerin (BCG).

In another embodiment, the administration regime can involve administering to a symptomatic subject a second infectious, replication-deficient arenavirus expressing a CMV antigen as described herein. In yet another embodiment, the administration regime can involve administering to an subject with a compromised immune system, especially transplant recipients, HIV-infected persons, a pregnant subject, a subject who has cancer, or a second infectious, replication-deficient arenavirus expressing a CMV antigen as described herein. In another embodiment, two or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein are administered to a subject who is a child of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 years of age suffering from or susceptible to, or are at risk for, an infection with CMV or reactivation of CMV.

In another embodiment, the administration regime can involve administering to a subject who is a child, a first replication deficient arenavirus expressing a CMV antigen, and administering to the same subject who is an adolescent a second replication deficient arenavirus expressing a CMV antigen. In a specific embodiment, the administration regime can involve administering to a subject who is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 years of age a first, replication-deficient arenavirus expressing a CMV antigen as described herein, and to the same subject who is 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 years of age a second infectious replication-deficient arenavirus expressing a CMV antigen.

In another embodiment, the administration regime can involve administering to a prepubescent subject a second infectious, replication-deficient arenavirus expressing a CMV antigen. In another embodiment, the administration regime can involve administering to an adolescent male, aged 12 to 18 years a second infectious, replication-deficient arenavirus expressing a CMV antigen as described herein. In another embodiment, the administration regime can involve administering to a female, aged 12 to 18 years a second infectious, replication-deficient arenavirus expressing a CMV antigen.

In another embodiment, administering two or more infectious, replication-deficient arenaviruses expressing a CMV antigen reduces the risk that an individual will develop an infection with CMV or reactivation of CMV by at least 10%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, compared with the manifestation of the symptoms of an infection CMV or reactivation of CMV in the absence of such treatment.

In another embodiment, administering two or more infectious, replication-deficient arenaviruses expressing a CMV antigen, administered separately, reduces the risk that an individual will develop an infection with CMV or reactivation of CMV by at least 10%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, compared with the manifestation of the symptoms of an infection CMV or reactivation of CMV in the absence of such treatment.

In another embodiment, administering two or more infectious, replication-deficient arenaviruses expressing a CMV antigen, administered sequentially, reduces the risk that an individual will develop an infection with CMV or reactivation of CMV by at least 10%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, compared with the manifestation of the symptoms of an infection CMV or reactivation of CMV in the absence of such treatment.

6.8 (b) Compositions

The invention furthermore relates to vaccines, immunogenic compositions, and pharmaceutical compositions comprising a genetically engineered arenavirus as described herein. Such vaccines and pharmaceutical compositions can be formulated according to standard procedures in the art.

In one embodiment, provided herein are compositions comprising two or more infectious, replication-deficient arenaviruses expressing a CMV antigen as described herein. See, e.g., Section 6.2. In a specific embodiments, the compositions described herein comprises administering to a subject a first infectious, replication-deficient arenavirus expressing a CMV antigen as described herein, e.g., in which the ORF encoding the GP of the S genomic segment is substituted with a nucleotide sequence encoding the CMV antigen. The CMV antigen can be but is not limited to:

-   -   a) a nucleotide sequence encoding a CMV glycoprotein gB or an         antigenic fragment thereof;     -   b) a nucleotide sequence encoding a CMV tegument protein pp65 or         an antigenic fragment thereof;     -   c) a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   d) a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   e) a nucleotide sequence encoding a CMV glycoprotein UL128 or an         antigenic fragment thereof;     -   f) a nucleotide sequence encoding a CMV glycoprotein UL130 or an         antigenic fragment thereof;     -   g) a nucleotide sequence encoding a CMV glycoprotein UL131A or         an antigenic fragment thereof;         and a second infectious, replication-deficient arenavirus         composition expressing a CMV antigen as described herein, e.g.,         in which the ORF encoding the GP of the S genomic segment is         substituted with a nucleotide sequence encoding the CMV antigen.         The CMV antigen can be but is not limited to:     -   a) a nucleotide sequence encoding a CMV glycoprotein gB or an         antigenic fragment thereof;     -   b) a nucleotide sequence encoding a CMV tegument protein pp65 or         an antigenic fragment thereof;     -   c) a nucleotide sequence encoding a CMV glycoprotein gH or an         antigenic fragment thereof;     -   d) a nucleotide sequence encoding a CMV glycoprotein gL or an         antigenic fragment thereof;     -   e) a nucleotide sequence encoding a CMV glycoprotein UL128 or an         antigenic fragment thereof;     -   f) a nucleotide sequence encoding a CMV glycoprotein UL130 or an         antigenic fragment thereof;     -   g) a nucleotide sequence encoding a CMV glycoprotein UL131A or         an antigenic fragment thereof.

In specific embodiments, provided herein are methods for treating and/or preventing a CMV infection comprising administering a first infectious, replication-deficient arenavirus expressing a first CMV antigen, selected from: a CMV tegument protein pp65 or an antigenic fragment thereof; a CMV glycoprotein gH or an antigenic fragment thereof; a CMV glycoprotein gL; a CMV glycoprotein UL128 or an antigenic fragment thereof; or an antigenic fragment thereof; a CMV glycoprotein UL130 or an antigenic fragment thereof; or a CMV glycoprotein UL131A or an antigenic fragment thereof, as described herein and a second infectious, replication-deficient arenavirus expressing a second CMV antigen, selected from: a nucleotide sequence encoding a CMV glycoprotein gB or an antigenic fragment thereof; a CMV tegument protein pp65 or an antigenic fragment thereof; a CMV glycoprotein gH or an antigenic fragment thereof; a CMV glycoprotein gL; a CMV glycoprotein UL128 or an antigenic fragment thereof; or an antigenic fragment thereof; a CMV glycoprotein UL130 or an antigenic fragment thereof; or a CMV glycoprotein UL131A or an antigenic fragment thereof.

In certain embodiments, provided herein are compositions suitable for a method of treating and/or preventing a CMV infection comprising administering two arenavirus construct expressing a CMV antigen as described herein. In a specific embodiment, the two arenavuris vector constructs express a CMV antigen.

In certain embodiments, provided herein are compositions comprising two or more arenavirus vector constructs expressing a CMV antigen as described herein. In specific embodiments, provided herein are compositions comprising three or more arenavirus vector constructs expressing a CMV antigen as described herein. In another embodiment, provided herein are compositions comprising four or more arenavirus vector constructs expressing a CMV antigen, five or more arenavirus vector constructs expressing a CMV antigen, six or more arenavirus vector constructs expressing a CMV antigen or 7 arenavirus vector constructs each expressing a CMV antigen as described herein or a combination thereof. In certain embodiments, the arenavirus can be LCMV.

In specific embodiments, the antigen is the CMV major envelope glycoprotein gB or a fragment thereof. (See, e.g., Section 6.2(a)). In more specific embodiments, the antigen is the CMV major envelope glycoprotein gB with a truncation of the carboxy-terminus. (See, e.g., Section 6.2(b) for truncated gB proteins).

In certain embodiments, the antigen is the CMV tegument protein pp65 or a fragment thereof. (See, e.g., Section 6.2(c)).

In certain embodiments, the antigen is a CMV pentameric complex protein. In another embodiment the CMV pentameric complex antigen is gH, gH (dTM), gL, UL128, UL131A, or UL130 or combinations thereof. (See, e.g., Section 6.2(d)).

In certain embodiments, the vector generated to encode one or more CMV antigens as described herein comprises one or more nucleic acids encoding a CMV antigen and combinations thereof as described. In specific embodiments the CMV antigens as described herein are separated by various linkers, spacers, and cleavage sites as described herein.

In another embodiment, the vector generated to encode one or more CMV antigens as described herein of the first infectious, replication-deficient arenavirus may be based on LCMV Clone 13 or LCMV MP strain. (See, e.g., Section 7.1).

In another embodiment, the vector generated to encode one or more CMV antigens as described herein of the second infectious, replication-deficient arenavirus may be based on LCMV Clone 13 or LCMV MP strain. (See, e.g., Section 7.1).

In a specific embodiment, provided herein are compositions suitable for a method of treating and/or preventing a CMV infection in a subject comprising administering to the subject a first infectious, replication-deficient arenavirus composition expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus composition expressing a CMV glycoprotein gB or an antigenic fragment thereof.

In a specific embodiment, provided herein are compositions suitable for a method of treating and/or preventing an infection in a subject comprising administering sequentially to the subject a first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or an antigenic fragment thereof.

In a specific embodiment, provided herein are compositions suitable for a an infection in a subject comprising administering simultaneously to the subject a first infectious, replication-deficient arenavirus expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or an antigenic fragment thereof.

In another embodiment, the first infectious, replication-deficient arenavirus composition expressing a CMV tegument protein pp65 or an antigenic fragment thereof is a primary vaccine antigen and the second infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB or an antigenic fragment thereof is a secondary vaccine antigen.

In a specific embodiment, provided herein is a composition comprising a first infectious, replication-deficient arenavirus composition expressing a CMV tegument protein pp65 or an antigenic fragment thereof and a second infectious, replication-deficient arenavirus composition expressing a CMV glycoprotein with a truncation of the carboxy-terminus. (See, e.g., Section 6.2(b) for truncated gB proteins).

In yet another embodiment, provided herein is the combined use of the replication-deficient arenaviruses compositions expressing a CMV antigen as described herein and one or more replication-defective virus vector compositions. In a more specific embodiment the replication-defective virus vector composition can be but is not limited to: poxviruses, adenoviruses, alphaviruses, herpes simplex viruses, paramyxoviruses, rhabdoviruses, poliovirus, adeno-associated virus, and Sendai virus, and mixtures thereof. In a specific embodiment, the poxvirus is a modified vaccine Ankara.

In another embodiment, two infectious, replication-deficient arenaviruses compositions have molar ratios ranging from about 1:1 to 1:1000, in particular including: 1:1 ratio, 1:2 ratio, 1:5 ratio, 1:10 ratio, 1:20 ratio, 1:50 ratio, 1:100 ratio, 1:200 ratio, 1:300 ratio, 1:400 ratio, 1:500 ratio, 1:600 ratio, 1:700 ratio, 1:800 ratio, 1:900 ratio, 1:1000 ratio.

In another embodiment, compositions are suitable for administration to the subjects in which two or more infectious, replication-deficient arenavirus compositions expressing a CMV antigen described herein is administered have, are susceptible to, or are at risk for a CMV infection or reactivation. In another embodiment, the subjects whom two or more infections, replication-deficient arenaviruses compositions expressing a CMV antigen described herein or a composition thereof is administered are infected with, are susceptible to, or are at risk for, an infection with CMV or reactivation with CMV.

In another embodiment, said two or more infectious, replication-deficient arenavirus compositions further comprise at least one other medicament for treating and/or preventing CMV infection or reactivation of CMV. Therapeutic medicaments include, but are not limited to, Valganciclovir, Ganciclovir, Foscarnet, Cidofovir, or Maribavir.

In another embodiment, compositions are suitable for administrating to a symptomatic subject a second infectious, replication-deficient arenavirus composition expressing a CMV antigen or a fragment thereof as described herein. In yet another embodiment, the compositions are suitable for administration to a subject with a compromised immune system, especially transplant recipients, HIV-infected persons, a pregnant subject, or a subject who has cancer, a second infectious, replication-deficient arenavirus composition expressing a CMV antigen described herein or a fragment thereof. In another embodiment, two or more infectious, replication-deficient arenavirus compositions expressing a CMV antigen as described herein or a fragment thereof are suitable for administrating to a subject who is a child of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 years of age suffering from or susceptible to, or are at risk for, an infection with CMV or reactivation of CMV.

In another embodiment, compositions are suitable for administrating to a subject who is a child, a first replication deficient arenavirus expressing a CMV antigen, and administering to the same subject who is an adolescent a second replication deficient arenavirus expressing a CMV antigen. In a specific embodiment, the administration regime can involve administering to a subject who is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or 17 years of age a first, replication-deficient arenavirus expressing a CMV antigen as described herein, and to the same subject who is 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 years of age a second infectious replication-deficient arenavirus expressing a CMV antigen.

In another embodiment, compositions are suitable for administering to a prepubescent subject a second infectious, replication-deficient arenavirus expressing a CMV antigen. In another embodiment, the administration regime can involve administering to an adolescent male, aged 12 to 18 years a second infectious, replication-deficient arenavirus expressing a CMV antigen as described herein. In another embodiment, the administration regime can involve administering to a female, aged 12 to 18 years a second infectious, replication-deficient arenavirus expressing a CMV antigen.

In another embodiment, two or more infectious, replication-deficient arenavirus compositions expressing a CMV antigen or a fragment thereof, as described herein reduce the risk that an individual will develop an infection with CMV or reactivation of CMV by at least 10%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, compared with the manifestation of the symptoms of an infection CMV or reactivation of CMV in the absence of such treatment.

In another embodiment, two or more infectious, replication-deficient arenavirus compositions expressing a CMV antigen or a fragment thereof, as described herein, administered separately, reduce the risk that an individual will develop an infection with CMV or reactivation of CMV by at least 10%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, compared with the manifestation of the symptoms of an infection CMV or reactivation of CMV in the absence of such treatment.

In another embodiment, two or more infectious, replication-deficient arenavirus compositions expressing a CMV antigen or a fragment thereof, as described herein, administered sequentially, reduce the risk that an individual will develop an infection with CMV or reactivation of CMV by at least 10%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, compared with the manifestation of the symptoms of an infection CMV or reactivation of CMV in the absence of such treatment.

In another embodiment, provided herein the invention provides a vaccine composition comprising a synergistic combination of two or more infectious replication-deficient arenaviruses expressing a CMV antigen.

In specific embodiments, provided herein is a pharmaceutical composition comprising an infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus See, e.g., Section 6.2(b) for truncated gB proteins). In another embodiment, provided herein is a pharmaceutical composition comprising a first infectious, replication deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus or a CMV tegument protein pp65 and a second infectious, replication deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus or a CMV tegument protein pp65.

In other embodiments, the pharmaceutical composition comprises an infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus that can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 3 over the entire length of the truncated gB protein. In more specific embodiments, the CMV glycoprotein gB has a truncation in the region of amino acids 773-906 of SEQ ID NO: 3. In a specific embodiment, the truncated gB protein consists of the amino acid sequence of SEQ ID NO: 18.

In certain embodiments, the truncation can of the glycoprotein gB can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 29, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, or 134 amino acids long. See section 6.2(b) for truncated gB proteins.

In certain embodiments, provided herein is an immunogenic composition comprising an infectious, replication-deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus (See, e.g., Section 6.2(b) for truncated gB proteins). In another embodiment, provided herein is an immunogenic composition comprising a first infectious, replication deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus or a CMV tegument protein pp65 and a second infectious, replication deficient arenavirus expressing a CMV glycoprotein gB with a truncation of the carboxy-terminus or a CMV tegument protein pp65.

In other embodiments, the immunogenic composition comprises a polypeptide that can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the amino acid sequence of SEQ ID NO: 3 over the entire length of the other gB. In more specific embodiments, the immunogenic composition has a truncation or deletion in the region of amino acids 773-906 of SEQ ID NO: 3. In yet other specific embodiments, the truncation or deletion 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 29, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, or 134 amino acids long. In certain embodiments, the immunogenic composition further comprises a pharmaceutically acceptable carrier.

6.9 Assays

Assay for Measuring Arenavirus Vector Infectivity Any assay known to the skilled artisan can be used for measuring the infectivity of an arenavirus vector preparation. For example, determination of the virus/vector titer can be done by a “focus forming unit assay” (FFU assay). In brief, complementing cells, e.g. HEK 293 cells expressing LCMV GP protein, are plated and inoculated with different dilutions of a virus/vector sample. After an incubation period, to allow cells to form a monolayer and virus to attach to cells, the monolayer is covered with Methylcellulose. When the plates are further incubated, the original infected cells release viral progeny. Due to the Methylcellulose overlay the spread of the new viruses is restricted to neighboring cells. Consequently, each infectious particle produces a circular zone of infected cells called a Focus. Such Foci can be made visible and by that countable using antibodies against LCMV-NP and a HRP-based color reaction. The titer of a virus/vector can be calculated in focus-forming units per milliliter (FFU/mL).

To determine the infectious titer (FFU/mL) of transgene-carrying vectors this assay is modified by the use of the respective transgene-specific antibody instead of anti-LCMV-NP antibody.

Serum ELISA Determination of the humoral immune response upon vaccination of animals (e.g. mice, guinea pigs) can be done by antigen-specific serum ELISA's (enzyme-linked immunosorbent assays). In brief, plates are coated with antigen (e.g. recombinant protein), blocked to avoid unspecific binding of antibodies and incubated with serial dilutions of sera. After incubation, bound serum-antibodies can be detected, e.g., using an enzyme-coupled anti-species (e.g. mouse, guinea pig)-specific antibody (detecting total IgG or IgG subclasses) and subsequent color reaction. Antibody titers can be determined as, e.g., endpoint geometric mean titer.

Neutralizing Assay in ARPE-19 cells Determination of the neutralizing activity of induced antibodies in sera is performed with the following cell assay using ARPE-19 cells from ATCC and a GFP-tagged virus. In addition supplemental guinea pig serum as a source of exogenous complement is used. The assay is started with seeding of 6.5×10³ cells/well (50 μl/well) in a 384 well plate one or two days before using for neutralization. The neutralization is done in 96-well sterile tissue culture plates without cells for 1 h at 37° C. After the neutralization incubation step the mixture is added to the cells and incubated for additional 4 days for GFP-detection with a plate reader. A positive neutralizing human sera is used as assay positive control on each plate to check the reliability of all results. Titers (EC50) are determined using a 4 parameter logistic curve fitting. As additional testing the wells are checked with a fluorescence microscope.

Plaque Reduction Assay In brief, plaque reduction (neutralization) assays for guinea pig cytomegalovirus are performed by use of an isolate of GPCMV tagged with green fluorescent protein, 5% rabbit serum was used as a source of exogenous complement, and plaques were enumerated by fluorescence microscopy. Neutralization titers were defined as the highest dilution of serum that resulted in a 50% reduction in plaques, compared with that in control (pre-immune) serum samples.

Neutralization Assay in guinea pig lung fibroblast (GPL) cells In brief, serial dilutions of test and control (pre-vaccination) sera were prepared in GPL complete media with supplemental rabbit serum (1%) as a source of exogenous complement. The dilution series spanned 1:40 through 1:5120. Serum dilutions were incubated with eGFP tagged virus (100-200 pfu per well) for 30 min at 37° C., and then transferred to 12-well plates containing confluent GPL cells. Samples were processed in triplicate. After 2 hours incubation at 37° C. the cells were washed with PBS, re-fed with GPL complete media and incubated at 37° C./5% CO₂ for 5 days. Plaques were visualized by fluorescence microscopy, counted, and compared to control wells. That serum dilution resulting in a 50% reduction in plaque number compared to controls was designated as the neutralizing titer.

qPCR LCMV RNA genomes are isolated using QIAamp Viral RNA mini Kit (QIAGEN), according to the protocol provided by the manufacturer. LCMV RNA genome equivalents are detected by quantitative PCR carried out on an StepOnePlus Real Time PCR System (Applied Biosystems) with SuperScript® III Platinum® One-Step qRT-PCR Kit (Invitrogen) and primers and probes (FAM reporter and NFQ-MGB Quencher) specific for part of the LCMV NP coding region. The temperature profile of the reaction is: 30 min at 60° C., 2 min at 95° C., followed by 45 cycles of 15 s at 95° C., 30 s at 56° C. RNA is quantified by comparison of the sample results to a standard curve prepared from a log 10 dilution series of a spectrophotometrically quantified, in vitro-transcribed RNA fragment, corresponding to a fragment of the LCMV NP coding sequence containing the primer and probe binding sites.

Western Blotting Infected cells grown in tissue culture flasks or in suspension are lysed at indicated timepoints post infection using RIPA buffer (Thermo Scientific) or used directly without cell-lysis. Samples are heated to 99° C. for 10 minutes with reducing agent and NuPage LDS Sample buffer (NOVEX) and chilled to room temperature before loading on 4-12% SDS-gels for electrophoresis. Proteins are blotted onto membranes using Invitrogens iBlot Gel transfer Device and visualized by Ponceau staining Finally, the preparations are probed with an primary antibodies directed against proteins of interest and alkaline phosphatase conjugated secondary antibodies followed by staining with 1-Step NBT/BCIP solution (INVITROGEN).

MHC-Peptide Multimer Staining Assay for Detection of Antigen-Specific CD8+ T-cell proliferation Any assay known to the skilled artisan can be used to test antigen-specific CD8+ T-cell responses. For example, the MHC-peptide tetramer staining assay can be used (see, e.g., Altman J. D. et al., Science. 1996; 274:94-96; and Murali-Krishna K. et al., Immunity. 1998; 8:177-187). Briefly, the assay comprises the following steps, a tetramer assay is used to detect the presence of antigen specific T-cells. In order for a T-cell to detect the peptide to which it is specific, it must both recognize the peptide and the tetramer of MHC molecules custom made for an antigen specific T-cell (typically fluorescently labeled). The tetramer is then detected by flow cytometry via the fluorescent label.

ELISPOT Assay for Detection of Antigen-Specific CD4+ T-cell Proliferation Any assay known to the skilled artisan can be used to test antigen-specific CD4+ T-cell responses. For example, the ELISPOT assay can be used (see, e.g., Czerkinsky C. C. et al., J Immunol Methods. 1983; 65:109-121; and Hutchings P. R. Et al., J Immunol Methods. 1989; 120:1-8). Briefly, the assay comprises the following steps: An immunospot plate is coated with an anti-cytokine antibody. Cells are incubated in the immunospot plate. Cells secrete cytokines and are then washed off. Plates are then coated with a second biotyinlated-anticytokine antibody and visualized with an avidin-HRP system.

Intracellular Cytokine Assay for Detection of Functionality of CD8+ and CD4+ T-cell Responses Any assay known to the skilled artisan can be used to test the functionality of CD8+ and CD4+ T cell responses. For example, the intracellular cytokine assay combined with flow cytometry can be used (see, e.g., Suni M. A. et al., J Immunol Methods. 1998; 212:89-98; Nomura L. E. et al., Cytometry. 2000; 40:60-68; and Ghanekar S. A. et al., Clinical and Diagnostic Laboratory Immunology. 2001; 8:628-63). Briefly, the assay comprises the following steps: activation of cells via specific peptides or protein, an inhibition of protein transport (e.g., brefeldin A) is added to retain the cytokines within the cell. After washing, antibodies to other cellular markers can be added to the cells. Cells are then fixed and permeabilized. The anti-cytokine antibody is added and the cells can be analyzed by flow cytometry.

Assay for Confirming Replication-Deficiency of Viral Vectors Any assay known to the skilled artisan that determines concentration of infectious and replication-competent virus particles can also be used as a to measure replication-deficient viral particles in a sample. For example, FFU assays (as described in [00225]) with non-complementing cells can be used for this purpose.

Furthermore, plaque-based assays are the standard method used to determine virus concentration in terms of plaque forming units (PFU) in a virus sample. Specifically, a confluent monolayer of non-complementing host cells is infected with the virus at varying dilutions and covered with a semi-solid medium, such as agar to prevent the virus infection from spreading indiscriminately. A viral plaque is formed when a virus successfully infects and replicates itself in a cell within the fixed cell monolayer (see, e.g., Kaufmann, S. H.; Kabelitz, D. (2002). Methods in Microbiology Vol. 32: Immunology of Infection. Academic Press. ISBN 0-12-521532-0). Plaque formation can take 3-14 days, depending on the virus being analyzed. Plaques are generally counted manually and the results, in combination with the dilution factor used to prepare the plate, are used to calculate the number of plaque forming units per sample unit volume (PFU/mL). The PFU/mL result represents the number of infective replication-competent particles within the sample.

Assay for Expression of Viral Antigen Any assay known to the skilled artisan can be used for measuring expression of viral antigens. For example, FFU assays (as described in [00225]) can be performed. For detection, mono- or polyclonal antibody preparation(s) against respective viral antigens are used (transgene-specific FFU).

Furthermore, Western Blotting (as described in [00231]) can be performed.

Animal Models The safety, tolerance and immunogenic effectiveness of vaccines comprising of an infectious, replication-deficient arenavirus expressing a CMV antigen described herein or a composition thereof can be tested in animals models. In certain embodiments, the animal models that can be used to test the safety, tolerance and immunogenic effectiveness of the vaccines and compositions thereof used herein include mouse, guinea pig, rat, and monkey. In a preferred embodiment, the animal models that can be used to test the safety, tolerance and immunogenic effectiveness of the vaccines and compositions thereof used herein include mouse.

Guinea pig model The preclinical evaluation of the immunogenicity and efficacy of HCMV vaccines is made difficult by the species specificity of CMV. However, in guinea pigs, guinea pig CMV (GPCMV) does cross the placenta to cause a congenital infection similar to human infection (Bourne N et al, JID 1996; Schleiss M et al, JID 2003). Furthermore, the structure of the placenta as well as the trimester-like pregnancy period of guinea pigs is similar to that in humans. In addition, as in humans, transplacental passage of maternal antibodies occurs. Based on these features the guinea pig model is been commonly used for the evaluation of vaccine strategies.

To investigate protective efficacy against congenital CMV infection Hartley guinea pigs can be immunized with test vaccine candidates and immunized guinea pigs can subsequently be allowed to breed. Pregnancies in guinea pig dams can be confirmed and monitored by palpatation. Pregnant dams can be challenged with GPCMV and pup mortality can be measured and protection rates be determined at parturition.

In certain embodiments, inclusion of heterologous domains from other viruses into the human CMV antigen results in induction of higher antibody levels. To test the generation of neutralizing antibodies, an assay can be conducted as follows: female guinea pigs are immunized three times on days 0, 21 and 42. Two weeks after the last vaccine dose, the immunized guinea pigs are allowed to breed. Pregnant guinea pigs are challenged at 40-50 days of gestation with GPCMV. Sera of vaccinated animals will be analyzed by ELISA and neutralization assays and blood samples will be obtained after challenge for detection of viremia by Real-Time PCR. Dams will be monitored until delivery, and survival and condition of the offspring will be analyzed in detail.

In certain embodiments, inclusion of heterologous domains from other viruses into the human CMV antigen results in induction of higher antibody levels.

7. EXAMPLES

7.1 Design of Arenavirus Vector Genome/Vector Construction

Following established approaches (U.S. Patent Application Publication No. US 2010/0297172 A1; and Flatz L. et al., Nat Med. 2010 March; 16(3): 339-345), rLCMV vaccine vectors expressing the respective CMV antigens or certain domains thereof were designed (FIG. 1).

Design of rLCMV vectors expressing CMV gB For generation of rLCMV vaccine vectors expressing the gB antigen of CMV various rLCMV-gB vector constructs (FIG. 2) were designed encoding selected parts of the gB protein. Respective constructs included rLCMV vectors encoding:

-   -   full-length wildtype gB (HK1-HgB(FL), SEQ ID NO: 1),     -   transmembrane region deleted (dTM) gB in which the amino acids         1-698 were fused to amino acids 775-906 (HK1-HgB(dTM), SEQ ID         NO: 4),     -   a C-terminally truncated gB consisting of the N-terminal 706         amino acids of gB (HK1-HgB(1-706), SEQ ID NO: 7),     -   a C-terminally truncated gB consisting of the N-terminal 691         amino acids of gB (HK1-HgB(1-691), SEQ ID NO: 10)     -   a C-terminally truncated gB consisting of the N-terminal 447         amino acids of gB (HK1-HgB(1-447), SEQ ID NO: 13),     -   a C-terminally truncated gB consisting of the N-terminal 772         amino acids of gB, encoding the ectodomain and the transmembrane         region of gB, followed by an artificial Arginine residue at         position 773 (HK1-HgB(dCt), SEQ ID NO: 16),     -   a gB construct consisting of the N-terminal 751 amino acids of         gB followed by the C-terminal 49 amino acids of Vesicular         Stromatitis Virus Protein G (HK1-HgB(VSVG-1), SEQ ID NO: 19),     -   a gB construct consisting of the N-terminal 706 amino acids of         gB followed by the C-terminal 49 amino acids of Vesicular         Stromatitis Virus Protein G (HK1-HgB(VSVG-2), SEQ ID NO: 22),     -   a C-terminally truncated gB consisting of the N-terminal 751         amino acids of gB followed by the C-terminal 37 amino acids of         Influenza hemagglutinin H3 (HK1-HgB(H3-1), SEQ ID NO: 25),     -   a C-terminally truncated gB consisting of the N-terminal 706         amino acids of gB followed by the C-terminal 37 amino acids of         Influenza hemagglutinin H3 (HK1-HgB(H3-2), SEQ ID NO: 28).

As the species specificity of CMV precludes animal efficacy studies of vaccines expressing human CMV antigens, not only rLCMV vectors encoding the gB sequence of human CMV (HCMV) have been generated, but also corresponding vectors expressing analogous sequences of guinea pig CMV (GPCMV) for some constructs, e.g. HK1-GPgB(FL), HK1-GPgB(FLuc), HK1-GPgB(dTM), HK1-GPgB(dTMuc), HK1-GPgB(1-706), HK1-GPgB(1-691), HK1-GPgB(1-447), HK1-GPgB(dCt). HK1-GPgB(FLuc) has been designed analogously to HK1-GPgB(FL) except that the furin-cleavage site located in the ectodomain of gB has been inactivated by mutation. HK1-GPgB(dTMuc) has been designed analogously to HK1-GPgB(dTM) except that the furin-cleavage site located in the ectodomain of gB has been inactivated by mutation. Vector constructs encoding GPCMV antigens enable pre-clinical immunogenicity and efficacy studies in the guinea pig model which presents the gold standard for CMV vaccine development. Similarly, constructs expressing the analogous sequences of mouse CMV gB were generated allowing for rapid and cost effective pre-screening of the individual vector design.

Analogously, an rLCMV vector has been constructed that expresses the full-length T-cell antigen pp65 from human CMV (HK1-Hpp65, SEQ ID NO: 34). In addition, a corresponding vector expressing the analogous sequences of guinea pig CMV (GPCMV) has been generated (HK1-GPpp65).

In addition, rLCMV vectors for expression of different parts of the pentameric complex (PC) of CMV, formed by the glycoproteins gH/gL, UL128, UL130, and UL131A, have been designed. In order to generate an rLCMV vector expressing the full complex, a polyprotein vector encoding the five proteins separated by Teschovirus 2A peptide (T2A) sequences (FIG. 3) has been designed (Donnelly MLL et al 2001, Gao S Y et al 2012, Kim J H et al 2011). Self-cleaving 2A peptides have been chosen as they are relatively small in size and show high cleavage efficiency between genes upstream and downstream of the 2A peptide (Donnelly MLL et al 2001, Gao S Y et al 2012, Kim J H et al 2011).

Respective constructs comprised

-   -   a vector encoding glycoprotein gH only (HK1-HgH, SEQ ID NO: 37)     -   a vector encoding a transmembrane domain deleted version of         glycoprotein gH (HK1-HgH(dTM), SEQ ID NO: 50).

Derivation of rLCMV vector constructs rLCMV vectors may differ in the LCMV strain from which the cDNA sequences are derived and the plasmid system used for their rescue. Clone 13 or MP strain LCMV are two possible strains used for the derivation of vectors. Studies comparing the effect of the rLCMV vector backbone, Clone 13 and MP, on the induction of immune responses has been evaluated using Hpp65, HgBdTM and GPgBdTM as transgenes as shown in FIG. 16-18. Four different approaches/plasmid systems may be used for vector rescue. In one approach, transcription of the short (S) and long (L) genomic segments of the viral vector is controlled by a murine-specific RNA polymerase I promoter and terminator. The polymerase and NP proteins are expressed from individual constructs under control of a polymerase II promoter. Substitution of GP by a CMV antigen in the cDNA system followed by transfection of the four plasmids in murine cells which provide the LCMV GP protein in trans leads to formation of vector particles which can be harvested from the supernatant of transfected cells. This approach is used in Flatz, et al., Proc. Natl. Acad. Sci. USA 2006, 103:4663.

In the second system, transcription of the S (including CMV antigen) and the L segment are under control of a T7 promoter, which necessitates the introduction of a fifth plasmid encoding T7 polymerase to drive expression from T7 promoters. The viral trans-acting factors (NP and L) are again co-expressed from different plasmids using an RNA polymerase II promoter. This system is adapted from Sanchez & de la Torre, Virology 2006 July, 350(2):370.

In the third system, transcription of the short (S) and long (L) genomic segments of the viral vector is controlled by a human RNA polymerase I promoter and appropriate terminator. The viral trans-acting factors (NP and L) are again co-expressed from different plasmids using an RNA polymerase II promoter.

In the fourth system, transcription of the short (S) and long (L) genomic segments of the viral vector is controlled by a human RNA polymerase I promoter and appropriate terminator. On the same plasmid, transcription of the viral trans-acting factors is driven by a polymerase II promoter which is designed to be directed in the opposite direction to drive transcription of positive strand RNA from the NP and L ORFs from the same template. Such an approach was used before to generate recombinant Influenza viruses and is described in Hoffmann E et al 2000. All rLCMV vectors described above can be produced according to established methodology (U.S. Patent Application Publication No. US 2010/0297172 A1; and Flatz L. et al., Nat Med. 2010 March; 16(3): 339-345). Other methods can also be used; e.g., different plasmid systems, different cells and different transfection methods can be used to generate the arenavirus vectors provided herein.

7.2 Vector Characterization

Characterization of rLCMV vectors expressing CMV gB Characterization of the generated vector constructs included analysis of viral replication and specific infectivity of host cells (FIG. 4).

FIG. 4 shows viral titers and infectivity of vector constructs HK1-HgB(FL), HK1-HgB(dTM), HK1-HgB(706), HK1-HgB(691), HK1-HgB(dCt), HK1-HgB(VSVG-1), HK1-HgB(VSVG-2), HK1-HgB(H3-1) and HK1-HgB(H3-2). The respective vector constructs showed similar peak titers and infectivity comparable to a control LCMV vector expressing the green-fluorescent-protein (HK1-GFP), indicating that there was no negative impact on vector production due to the size and nature of the transgenes.

In order to analyze vector replication, growth curves were performed using suspension HEK 293 cells expressing LCMV GP. Respective cells were seeded with cell density of 3×10⁵ cells/ml and infected with individual vectors (HK1-HgB(dTM), HK1-HgB(dCt), HK1-HgB(VSVG-1), HK1-HgB(H3-2) and HK1-HgB(691)) at MOI of 0.001. Samples were drawn every 24 hours and analysed by FFU assay (FIG. 5). All tested vectors exhibited similar growth kinetics and peak titers compared to HK1-GFP indicating that the individual gB transgenes did not interfere with vector replication to a greater extent than the small reportergene GFP.

Western blot experiments were used to confirm presence of the gB antigen for all tested constructs, exemplary data are shown in FIG. 6. Uncleaved precursors of full length gB are expected to band at ˜160 kDa whereas cleaved gB consists of a surface component with an estimated molecular mass of 116 kDa that is linked by disulfide bonds to a transmembrane component with an estimated molecular mass of 55 kDa. However, due to use of a monoclonal primary antibody only two bands representing the uncleaved gB protein and the smaller cleavage product of gB are expected to be visable on the blot. Full length gB (lane 7) banded at the expected range of ˜160 kDa, whereas all remaining constructs showed bands of lower size which can be explained by the deletion or exchange of at least part of the gB cytoplasmic domain. Analogously, the transmembrane part of full length gB (lane 7) bands at ˜60 kDa (slightly higher than expected) and all gB derivates exhibit cleavage products of lower size. In general HK1-gB(FL) and HK1-gB(dTM) exhibited weaker gB bands compared to all other vectors.

Comparison of immunogenicity of HK1-GPgB(FL), HK1-GPgB(dTM) and HK1-GPgB(dTMuc) Next, the immunogenicity of HK1-GPgB(FL), HK1-GPgB(dTM) and HK1-GPgB(dTMuc) were analyzed and compared in mice (FIG. 7). C57BL/6 mice were immunized subcutaneously with 6.7×10⁴ FFU/dose of the respective vectors on days 0, 21 and 42 of the experiment. Sera of immunized mice were collected on days 21, 42 and 63 of the experiment and anti-gB antibody titers were measured by ELISA. An analogous rLCMV vector expressing the green fluorescent protein (HK1-GFP) was used as a control. The control vector was used at a concentration of 9.2×10⁵ FFU per injection.

HK1-GPgB(dTM) and HK1-GPgB(dTMuc) induced significantly higher antibody titers than HK1-GPgB(FL) after subcutaneous injection in mice.

Comparison of immunogenicity of HK1-GPgB(dTM) vaccine vector administered by intramuscular or subcutaneous route at different concentrations Next, the immunogenicity of HK1-GPgB-dTM, when administered at different doses and different injection routes, was analyzed systematically (FIGS. 8A and B).

These analyses demonstrated that HK1-GPgB-dTM induced higher antibody responses following intramuscular injection (FIG. 8A) compared to subcutaneous administration. Among the tested immunization doses, vaccine doses of 2×10⁶ and 6.7×10⁴ FFU/dose resulted in comparably high antibody titers.

Comparison of the intramuscular and intradermal route of immunization. The induction of humoral as well as CD8+ T cell responses was analyzed after immunization with different concentrations of either HK1-HgB(dCt) (FIG. 8C) or HK1-Hpp65 (FIG. 8D) using the intramuscular and the intradermal route. Respective results demonstrate that significantly higher titers of antigen-specific antibodies were elicited by the intramuscular compared to the intradermal route at a dose of 5.6×10⁵ FFU (FIG. 8C, groups 1 and 3) indicating that no dose sparing effect could be achieved when the vaccine was administered via the intradermal route. Similarly, higher CD8+ T cell responses were observed after intramuscular injection compared to intradermal immunization at a dose of 6,7×10⁵ FFU (FIG. 8D groups 1 and 3).

Comparison of the immunogenicity of HK1-HgB(dTM), HK1-HgB(1-706), HK1-HgB(1-691), HK1-HgB(dCt), HK1-HgB(H3-1), HK1-HgB(H3-2), HK1-HgB(VSVG-1), HK1-HgB(VSVG-2) and a recombinant gB protein mixed with adjuvant The immunogenicity of HK1-HgB(dTM), HK1-HgB(1-706), HK1-HgB(1-691), HK1-HgB(dCt), HK1-HgB(H3-1), HK1-HgB(H3-2), HK1-HgB(VSVG-1), HK1-HgB(VSVG-2) and a recombinant gB protein mixed with adjuvant was analyzed in mice. C57BL/6 mice were immunized intramuscularly with 1×10⁵ FFU/dose of the respective vectors or 5 μg of a recombinant gB protein mixed 1:1 with adjuvant on days 0 and 21 of the experiment. Sera of immunized mice were collected prior to each vaccine dose on days 0, 21 as well as in intervals of three weeks on days 42, 63, 84 and 105 of the experiment. Generated sera were tested for the level of anti-HCMVgB IgG antibodies by ELISA and for the presence of neutralizing antibodies by Neutralization Assay in ARPE-19 cells.

Statistical analysis of the respective ELISA data (FIG. 9) revealed comparable antibody induction of the recombinant gB protein (mixed with adjuvant) and all tested rLCMV-gB constructs. In addition, generated results indicate that very long-lasting immune responses can already be achieved after two immunizations as antibody levels reach a plateau after the second immunization.

Functionality of the induced antibodies In order to test the functionality of the induced antibodies, the sera of vaccinated animals were further analyzed by Neutralization Assay in ARPE-19 cells. The neutralizing activity of the induced antibodies, present in the sera of immunized mice, collected on day 42, was measured in epithelial ARPE-19 cells (FIG. 10). Respective results indicate that all tested rLCMV-gB constructs induced higher HCMV neutralizing antibody levels than the recombinant subunit gB protein mixed with adjuvant. However, HgB(dTM) induced significantly lower levels of HCMV neutralizing antibodies than all other tested rLCMV-gB vectors.

Analysis of individual IgG subclasses The sera of selected experimental groups (vaccinated with HK1-HgB(dTM), HK1-HgB(1-706), HK1-HgB(1-691), HK1-HgB(H3-2), HK1-HgB(VSVG-1), and recombinant gB protein mixed with adjuvant), collected on day 42, were analyzed by HCMVgB-specific IgG subclass ELISA (FIG. 11). The respective analysis revealed predominant induction of IgG2c by rLCMV-gB constructs whereas the recombinant gB protein mixed with adjuvant induced mainly IgG1. This data point to a type 1 biased immune response induction by rLCMV-gB vectors which seems to be significantly different from the type 2 biased response induced by the gB subunit protein.

Immunogenicity of HK1-GPgB(dTM) in guinea pigs Hartley guinea pigs were immunized by intramuscular injection with different concentrations (1.54×10⁷, 1.54×10⁶, 1.54×10⁵ and 1.54×10⁴ FFU/dose) of HK1-GPgB-dTM on days 0, 21 and 42 of the experiment. For control purposes one animal received no vaccine or buffer. Sera of immunized animals were collected on days 0, 21, 42 and 63 of the experiment and anti-GPgB antibody titers were analyzed by GPgB-specific IgG ELISA. A GPCMV positive serum was used as control.

ELISA data show that already after single intramuscular immunization (prime), HK1-GPgB(dTM) induced anti-GPgB antibody responses of considerable magnitude in a dose-dependent manner (FIG. 12). These responses could efficiently be augmented when the same vector was re-administered three weeks after prime and reached a plateau of IgG response after two injections for the three highest doses (1.54×10⁷, 1.54×10⁶, 1.54×10⁵) of HK1-GPgB(dTM). The values reached are similar to a control serum used (generated 30 dpi with 1×10⁵ pfu GPCMV. A significant lower response was induced by the lowest dose group (1.54×10⁴).

Respective sera were further analyzed for the presence of virus neutralizing antibodies by plaque reduction assay (FIG. 13). Results showed the induction of neutralizing antibodies in guinea pigs upon immunization with HK1-GPgB(dTM). Respective data point to a minimum dose in the range of >1.54×10⁵ of HK1-GpgB(dTM) required to elicit robust neutralizing antibodies. Based on the available data a dose of 1.54×10⁶ FFU has been selected to study the protective effect of HK1-GpgB(dTM) in the congenital model of GPCMV infection (compare FIG. 23).

Characterization of rLCMV vectors expressing CMV pp65 In order to characterize the growth kinetics and the infectivity of the generated HK1-Hpp65 vector, LCMV GP expressing HEK 293 suspension cells were infected with HK1-Hpp65 at MOI=0.001. At defined timepoints (2 h, 24 h, 48 h, 72 h and 96 h) after infection samples of cell supernatant were drawn and analyzed by FFU assay and qPCR (FIG. 14).

Data in FIG. 14 show comparable replication kinetics, peak titers and infectivity of vector construct HK1-Hpp65 and control vector HK1-GFP, indicating that the pp65 antigen does not negatively influence vector growth or infectivity. Lower particle infectivity ratios were observed at later timepoints.

To confirm the expression of the pp65 antigen, LCMV GP expressing HEK 293 suspension cells were infected with HK1-Hpp65 or a negative control vector HK1-GFP and were harvested and lysed 96 h post infection and subsequently analyzed by Western Blotting using a monoclonal anti HCMV pp65 primary antibody and an appropriate alkaline phosphatase conjugated secondary antibody (FIG. 15).

Next the immunogenicity of HK1-Hpp65 and HK3-Hpp65 was analyzed in C57BL/6 mice to examine the effect of different LCMV vector backbones (HK1 (clonel3), HK3 (MP)). C57BL/6 mice were vaccinated i.m. (50 μL/thigh; total 100 μL/mouse) with a target dose of 1×10⁴ FFU of HK1-Hpp65 (Group 1) or HK3-Hpp65 (Group 2). Non-vaccinated mice were used as a control (Group 7). The induction of cellular immune responses was determined by flow cytometry on day 10 after injection, analysing cytokine production (IL-2, IFN-g, TNF-α) of CD4+ and CD8+ T cells. A Hpp65 peptide pool (based on Shedlock D. J. et al; Human Vaccines & Immunotherapeutics 2012) was used for the re-stimulation of splenocytes.

After single intramuscular injection HK1-Hpp65 and HK3-Hpp65 induced HCMV-specific CD8+(and CD4+) T cell responses of considerable magnitude. The frequency of CD8+ T cell responses, analyzed 10 days after single injection, was higher than observed for CD4+ T cell responses (FIGS. 16 A and B, respectively). Based on the vector backbone (HK1 or HK3) there was no difference in the induction of CD4+ T cells observed. In contrast, higher CD8+ T cells responses were induced by HK1-pp65 compared to HK3-Hpp65. (C) HCMV-specific CD8+ T cell responses of similar magnitude were observed 10 days (day 66 of experiment) after single intramuscular injection (day 56 of experiment) with HK1-Hpp65 (Group 3) and HK3-Hpp65 (Group 4) in mice that had previously been immunized twice (8 and 4 weeks before; i.e. days 0 and 28 of experiment) with HK1-HgB(dTM). Respective results indicate that the induction of antigen-specific CD8+ T cell responses had not been impaired by vector-immunity due to prior immunization with the same vector backbone.

The effect of the rLCMV vector backbone, HK1 (Clone 13) or HK3 (MP), on the induction of an immune response was also evaluated using GPgBdTM (FIG. 17) and HgBdTM (FIG. 18) as transgenes.

To examine the effect of different vector backbones on the immunogenicity of GPgB-dTM construct, C57BL/6 mice were vaccinated i.m. on days 0 and 28 with a target dose of 1×10⁴ FFU of respective vectors. Sera from individual animals were generated prior to each vaccine dose (days 0, 28) as well as four weeks (day 56) after the last (second) injection. All sera were tested for the level of GPgB-specific IgG antibodies by ELISA; ELISA data are expressed as geometric mean GPgB-specific IgG endpoint titer. Statistical analysis of data presented in FIG. 17 indicate that the response induced by HK1-GPgB(dTM) is superior to HK3-GPgB(dTM).

To examine the effect of different vector backbones on the immunogenicity of HgB-dTM construct, C57BL/6 mice were vaccinated i.m. on days 0 and 28 with a target dose of 1×10⁴ FFU of respective vectors. Sera from individual animals were generated prior to each vaccine dose (days 0, 28) as well as four weeks (day 56) after the last (second) injection. All sera were tested for the level of HgB-specific IgG antibodies by ELISA; ELISA data are expressed as geometric mean HgB-specific IgG endpoint titer. Statistical analysis of data presented in FIG. 18 indicate that the response induced by HK1-HgB(dTM) and HK3-HgB(dTM) are not significantly different.

To determine the optimal LCMV strain to use with HEK 293 T cells, as shown in FIG. 19, HEK 293T cells were seeded in M6 well culture wells at a density of 500,000 cells per well. The next day, they were infected at a multiplicity of infection of 0.05 by MP, Pasteur, Clone 13 and WE54 strains. Supernatant was harvested at the indicated time points and viral titres were determined by immunofocus assay. Symbols represent the mean of two wells.

Immunogenicity of HK1-HgB(dCt) in rabbits New Zealand white rabbits were immunized by intramuscular injection with different concentrations (2.0×10², 4.4×10⁴ and 4.5×10⁶ FFU/dose) of HK1-HgB(dCt) on days 0 and 28 of the experiment. Sera of immunized animals were collected on days 0, 28 and 42 of the experiment and anti-HgB antibody titers were analyzed by HgB-specific IgG ELISA.

ELISA data show that already after single intramuscular immunization (prime) higher doses (4.4×10⁴ and 4.5×10⁶ FFU/dose) of HK1-HgB(dCt) induced anti-HgB antibody responses of considerable magnitude in a dose-dependent manner (FIG. 20). These responses could efficiently be augmented when the same vector was re-administered four weeks after prime. Injection of 4.5×10⁶ FFU/dose of HK1-HgB(dCt) induced statistically significant higher antibody responses than a 4.4×10⁴ FFU/dose at days 28 and 42.

Duration of antibody responses and comparison of different immunization schedules Different injection schedules were compared in regard to the level as well as the duration of antibody responses, induced upon immunization with HK1-HgB(H3-2), HK1-HgB(VSVG-1), and a recombinant gB protein mixed with adjuvant (FIG. 21A) or HK1-HgB(H3-2), HK1-HgB(VSVG-1), HgB(dTM), HK1-HgB(dCt) and a recombinant gB protein mixed with adjuvant (FIG. 21B). C57BL/6 mice were immunized intramuscularly with 1×10⁵ FFU/dose of the respective vectors or 5 μg of a recombinant gB protein mixed 1:1 with adjuvant on days 0, 21 and 42 (FIG. 21A) or on days 0, 21 and 105 (FIG. 21B) of the experiment. Sera of immunized mice were collected on days 21, 42, 63, 91, 119, 147 and 175 (FIG. 21A) or on days 21, 42, 63, 84, 105 and 126 (FIG. 21B) of the experiment. Generated sera were tested for the level of anti-HCMVgB IgG antibodies by ELISA. Respective ELISA data indicate that maximum antibody levels can be achieved by two immunizations and that induced humoral responses are very long-lasting.

No negative interference by simultaneous injection of two vectors In order to investigate a potential interference of different LCMV vector constructs, the induction of B and CD8+ T cell responses was analyzed after immunization with HK1-HgB(dCt) alone, HK1-Hpp65 alone or simultaneous injection of HK1-HgB(dCt) and HK1-Hpp65. C57BL/6 mice were immunized intramuscularly with 9×10⁴ FFU/dose of HK1-HgB(dCt) alone, 9×10⁴ FFU/dose of HK1-Hpp65 alone or 9×10⁴FFU/dose of each HK1-HgB(dCt) and HK1-Hpp65 together on days 0 and 28. The induction of anti-HCMVgB antibodies (FIG. 22A) or pp65-specific CD8+ T cell responses (FIG. 22B) was monitored 49 days after the first injection. No significant difference in anti-HCMVgB antibody levels (FIG. 22A) or pp65-specific CD8+ T cell responses (FIG. 22B) could be observed between the monovalent (HK1-HgB(dCt) or HK1-Hpp65 only) and the bivalent (HK1-HgB(dCt) and HK1-Hpp65) vaccine indicating a lack of negative interference when two rLCMV vectors are mixed and co-injected.

LCMV vectors protect pups against congenital CMV infection in the guinea pig model The preclinical evaluation of the protective efficacy against congenital CMV infection of HCMV vaccines is made difficult by the species specificity of CMV. However, guinea pig CMV (GPCMV) does cross the placenta to cause a congenital infection similar to human infection (Bourne N et al, JID 1996; Schleiss M et al, JID 2003). In addition, the structure of the placenta as well as the trimester-like pregnancy period and the transplacental passage of maternal antibodies are similar in guinea pigs and humans. Based on these features the guinea pig model is the best available animal model for the evaluation of CMV vaccine efficacy against congenital infection.

Hartley guinea pigs were immunized intramuscularly three times on days 0, 21 and 42 with HK1-GPgB(dTM), HK1-GPpp65 or buffer (control group). About two weeks after the last vaccine dose, the immunized guinea pigs were allowed to breed. Pregnant guinea pigs were challenged at ˜45 days of gestation with GPCMV and were subsequently monitored until delivery. Analysis of the survival of offspring revealed a significant reduction in pup mortality in dams immunized with HK1-GPgB(dTM) (p=0.026) or HK1-GPpp65 (p=0.032) alone prior to breeding (FIG. 23). Higher rates of protection can be anticipated after vaccination with a combination of rLCMV vector constructs expressing gB and pp65. See e.g., FIG. 28.

To determine the safety (virulence and virus replication) of rLCMV vectors, specific mice, highly susceptible to LCMV infection, have been inoculated intracerebrally on day 0 with HK3-Hpp65 or HK3-Mpp65, a replication-deficient LCMV vector derived from the MP strain of LCMV expressing the pp65 antigen from mouse CMV. Mice have subsequently been monitored for signs of illness. The presence of replicating virus has been analyzed in brain tissues collected on day 28 or earlier in case of illness.

No signs of illness and no virus replication could be observed in AG129 mice, which are deficient in IFN α/β and γ receptors and are thus highly susceptible to LCMV infection, 28 days after intracerebral inoculation of different doses of HK3-Hpp65 or HK3-Mpp65 (FIG. 24A). In contrast, AG129 mice inoculated with wildtype LCMV showed signs of disease and thus had to be euthanized on day 7.

Similarly, no virus replication could be observed in T and B cell deficient RAG−/− mice, which are also highly susceptible to LCMV infection, 28 days after intracerebral inoculation of different doses of HK3-Hpp65 or HK3-Mpp65 (FIG. 24B). High doses of replicating virus could be observed in RAG−/− mice inoculated with wildtype LCMV.

Immunogenicity of HK1-GPgB(dCt) and HK1-GPpp65 in Guinea Pigs

Hartley guinea pigs (18 animals/group) were immunized by intramuscular injection with 8×10⁵ FFU/dose of HK1-GPgB(dCt) (group 1), 8×10⁵ FFU/dose of HK1-GPpp65 (group 2), or 8×10⁵ FFU/dose of each HK1-GPgB(dCt) and HK1-GPpp65 (group 3) on days 0, 31 and 72 (group 1)/days 0, 31 and 70 (group 2)/days 0, 34 and 70 (group 3) of the experiment. In addition, Hartley guinea pigs (18 animals/group) were immunized by subcutaneous injection with 50 μg of subunit gB protein, formulated in Complete Freund's Adjuvant (group 4) on days 0, 46 and 76. Sera of immunized animals were collected on days 0, 28, 52, 103 and 155 of the experiment and anti-GPgB antibody titers were analyzed by GPgB-specific IgG ELISA using a sera pool with assigned anti-gB antibody titer as a reference standard.

ELISA data show that already after single immunization HK1-GPgB(dCt) induced anti-GPgB antibody responses of considerable magnitude (FIG. 25). These responses could be efficiently augmented when the same vector was re-administered one month after the first vaccination. Anti-GPgB antibody responses induced by immunization with HK1-GPgB(dCt) alone were in a similar range as those induced after vaccination with HK1-GPgB(dCt) in combination with HK1-GPpp65. Importantly, significantly higher levels of anti-GPgB antibodies were stimulated after immunization with HK1-GPgB(dCt) than after vaccination with a subunit gB protein formulated in Complete Freund's Adjuvant.

Neutralization Data

Respective sera were further analyzed for the presence of virus neutralizing antibodies by Neutralization Assay in GPL cells (FIG. 26). Results showed the induction of neutralizing antibodies in guinea pigs upon immunization with HK1-GPgB(dCt) alone (group 1) or HK1-GPgB(dCt) in combination with HK1-GPpp65 (group 3). Consistent with the ELISA data (FIG. 25) HK1-GPgB(dCt) induced significantly (P<0.0001, unpaired t test) higher levels of neutralizing antibodies than a subunit gB protein formulated in Complete Freund's Adjuvant. Unexpectedly, the combination of HK1-GPgB(dCt) with HK1-GPpp65 (Group 3) elicited significantly (P=0.0003, unpaired t test) more potently neutralizing sera than HK1-GPgB(dCt) alone (Group 1).

T Cell Data

In order to analyze the induction of pp65-specific T cell responses in vaccinated animals, splenocytes were isolated from Hartley guinea pigs immunized intramuscularly with 8×10⁵ FFU/dose of HK1-GFP (group 1), 8×10⁵ FFU/dose of HK1-GPpp65 (group 2) or 8×10⁵ FFU/dose of each HK1-GPgB(dCt) and HK1-GPpp65 (group 3). Three animals from each vaccine group (group 1, group 2, and group 3) were sacrificed after 2 doses of vaccine (animals were sacrificed at 43, 40, and 37 days post-second dose of vaccine, respectively). Three additional animals from each vaccine group were sacrificed at 7 days post-dose 3 in order to analyze whether a third vaccine dose further augments the pp65-specific T cell response, compared to two doses of vaccine.

Isolated splenocytes were analyzed by ELISPOT assay using pools of pp65 peptides for re-stimulation. Respective peptides (Sigma-Aldrich, St. Louis, Mo.) were designed to span pp65 in 9 amino acids long fragments with 5 amino acid overlaps (140 total peptides). Peptides were allocated into pools containing 11 or 12 peptides. The magnitude of each animal's response is the cumulative difference (“area under the curve”) between the peptide re-stimulated splenocytes and splenocytes restimulated with the DMSO (vehicle) control, for each peptide pool.

As shown in FIG. 27 A, pp65-specific IFN-γ producing splenocytes were induced in animals vaccinated with HK1-GPpp65 alone (group 2) as well as in animals vaccinated with HK1-GPpp65 in combination with HK1-GPgB(dCt) (group 3). In both vaccine groups, higher average numbers of pp65-specific IFN-γ producing splenocytes were observed after three vaccine doses compared to two doses.

While the small group sizes (n=3) prevent direct statistical comparison between vaccine groups after either 2 or 3 doses of vaccine, statistical comparisons can be made between combined vaccination groups, i.e., combining the data from the 2 dose group and 3 dose group together for each vaccine (group 1, group 2, and group 3) (FIG. 27 B). Respective analysis revealed that animals vaccinated with HK1-GPpp65 (group 2) had a significantly increased number of pp65-specific splenocytes per animal compared to HK1-GFP controls (group 1). Similarly, the HK1-GPgB(dCt)/HK1-GPpp65 vaccine group (group 3) also had a significantly increased number of pp65-specific splenocytes compared to HK1-GFP controls (group 1). No statistically significant difference between the vaccine groups 2 and 3 could be observed indicating that the presence of gB did not interfere with the pp65 response.

Protection Data

LCMV vectors protect pups against congenital CMV infection in the guinea pig model. The preclinical evaluation of the protective efficacy against congenital CMV infection of HCMV vaccines is made difficult by the species specificity of CMV. However, guinea pig CMV (GPCMV) does cross the placenta to cause a congenital infection similar to human infection (Bourne N et al, JID 1996; Schleiss M et al, JID 2003). In addition, the structure of the placenta as well as the trimester-like pregnancy period and the transplacental passage of maternal antibodies are similar in guinea pigs and humans. Based on these features the guinea pig model is the best available animal model for the evaluation of CMV vaccine efficacy against congenital infection.

Hartley guinea pigs (18 animals/group) were immunized intramuscularly three times (on days 0, ˜30 and ˜70) with 8×10⁵ FFU/dose of HK1-GFP (group 1), 8×10⁵ FFU/dose of HK1-GPgB(dCt) (group 2), 8×10⁵ FFU/dose of HK1-GPpp65 (group 3) or 8×10⁵ FFU/dose of each HK1-GPgB(dCt) and HK1-GPpp65 (group 4). Approximately one month after the last vaccine dose, the immunized guinea pigs were allowed to breed. Pregnancies in guinea pig dams were confirmed and monitored by palpatation. Pregnant dams were challenged in the third trimester of gestation with GPCMV and were subsequently monitored until delivery. Analysis of the survival of offspring (FIG. 28) revealed a reduction in pup mortality in dams immunized with HK1-GPgB(dCt) or HK1-GPpp65 alone compared to the control group. Vaccination with HK1-GPgB(dCt) conferred better protection than HK1-GPpp65. Even higher rates of protection could be observed after vaccination with a combination of HK1-GPgB(dCt) and HK1-GPpp65. A high mortality rate in the control group (group 1) indicates stringent challenge conditions.

Equivalents and Incorporation by Reference: The embodiments described herein are intended to be merely exemplary, and those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures described herein. All such equivalents are considered to be within the scope of the present invention and are covered by the following embodiments. All references (including patent applications, patents, and publications) cited herein are incorporated herein by reference in their entireties and for all purposes to the same extent as if each individual publication or patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety for all purposes. 

What is claimed:
 1. A pharmaceutical composition comprising a first infectious, replication-deficient arenavirus viral vector engineered to contain a genome with the ability to amplify and express its genetic information in infected cells but unable to produce further infectious progeny particles in normal, not genetically engineered cells, wherein one arenavirus open reading frame is removed and replaced by a first nucleotide sequence selected from the group consisting of: a) a nucleotide sequence encoding a cytomegalovirus glycoprotein B (gB) or an antigenic fragment thereof; b) a nucleotide sequence encoding a cytomegalovirus tegument protein pp65 or an antigenic fragment thereof; c) a nucleotide sequence encoding a cytomegalovirus glycoprotein H (gH) or an antigenic fragment thereof; d) a nucleotide sequence encoding a cytomegalovirus glycoprotein L (gL) or an antigenic fragment thereof; e) a nucleotide sequence encoding a cytomegalovirus UL128 protein or an antigenic fragment thereof; f) a nucleotide sequence encoding a cytomegalovirus UL130 protein or an antigenic fragment thereof; and g) a nucleotide sequence encoding a cytomegalovirus UL131A protein or an antigenic fragment thereof, and a second infectious, replication-deficient arenavirus viral vector engineered to contain a genome with the ability to amplify and express its genetic information in infected cells but unable to produce further infectious progeny particles in normal, not genetically engineered cells, wherein one arenavirus open reading frame is removed and replaced by a second nucleotide sequence selected from the group consisting of: a) a nucleotide sequence encoding a cytomegalovirus glycoprotein B (gB) or an antigenic fragment thereof; b) a nucleotide sequence encoding a cytomegalovirus tegument protein pp65 or an antigenic fragment thereof; c) a nucleotide sequence encoding a cytomegalovirus glycoprotein H (gH) or an antigenic fragment thereof; d) a nucleotide sequence encoding a cytomegalovirus glycoprotein L (gL) or an antigenic fragment thereof; e) a nucleotide sequence encoding a cytomegalovirus UL128 protein or an antigenic fragment thereof; f) a nucleotide sequence encoding a cytomegalovirus UL130 protein or an antigenic fragment thereof; and g) a nucleotide sequence encoding a cytomegalovirus UL131A protein or an antigenic fragment thereof wherein the first and second nucleotide sequences are different.
 2. The pharmaceutical composition of claim 1, wherein the first nucleotide sequence encodes the cytomegalovirus gB or fragment thereof, and wherein the second nucleotide sequence encodes the cytomegalovirus tegument protein pp65 or a fragment thereof.
 3. The pharmaceutical composition of claim 1, wherein the first nucleotide sequence encodes the cytomegalovirus gB with a truncation of the carboxy-terminus, and wherein the second nucleotide sequence encodes the cytomegalovirus tegument protein pp65 or a fragment thereof.
 4. The pharmaceutical composition of claim 3, wherein the cytomegalovirus gB with a truncation of the carboxy-terminus is at least 80%, 85%, 90%, 95%, 98%, 99% or at least 100% identical to the amino acid sequence of SEQ ID NO: 3 or SEQ ID NO: 60 over the entire length of the truncated gB, wherein the truncation is in the region of amino acids 772-906 of SEQ ID NO: 3 or SEQ ID NO: 60, respectively.
 5. The pharmaceutical composition of claim 4, wherein the truncation is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 29, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, or 134 amino acids long.
 6. The pharmaceutical composition of claim 1, wherein the composition is suitable for intramuscular administration.
 7. The pharmaceutical composition of claim 3, wherein the cytomegalovirus gB with a truncation of the carboxy-terminus comprises an amino acid sequence that is 100% identical to SEQ ID NO:
 18. 8. The pharmaceutical composition of claim 3, wherein the cytomegalovirus tegument protein pp65 comprises an amino acid sequence that is 100% identical to SEQ ID NO:
 36. 9. The pharmaceutical composition of claim 1, wherein the arenavirus open reading frame encoding the glycoprotein (GP) within the S segment of the first arenavirus viral vector is removed and replaced by the first nucleotide sequence.
 10. The pharmaceutical composition of claim 1, wherein the arenavirus open reading frame encoding the glycoprotein (GP) within the S segment of the second arenavirus viral vector is removed and replaced by the second nucleotide sequence.
 11. The pharmaceutical composition of claim 3, wherein the cytomegalovirus gB with a truncation of the carboxy-terminus comprises an amino acid sequence that is at least 80% identical to SEQ ID NO:
 18. 12. The pharmaceutical composition of claim 3, wherein the cytomegalovirus gB with a truncation of the carboxy-terminus comprises an amino acid sequence that is at least 85% identical to SEQ ID NO:
 18. 13. The pharmaceutical composition of claim 3, wherein the cytomegalovirus gB with a truncation of the carboxy-terminus comprises an amino acid sequence that is at least 90% identical to SEQ ID NO:
 18. 14. The pharmaceutical composition of claim 3, wherein the cytomegalovirus gB with a truncation of the carboxy-terminus comprises an amino acid sequence that is at least 95% identical to SEQ ID NO:
 18. 15. The pharmaceutical composition of claim 3, wherein the cytomegalovirus gB with a truncation of the carboxy-terminus comprises an amino acid sequence that is at least 98% identical to SEQ ID NO:
 18. 16. The pharmaceutical composition of claim 3, wherein the cytomegalovirus gB with a truncation of the carboxy-terminus consists of an amino acid sequence that is 100% identical to SEQ ID NO:
 18. 17. The pharmaceutical composition of claim 3, wherein the first nucleotide sequence encodes a cytomegalovirus gB wherein: (i) the cytoplasmic domain of the cytomegalovirus gB has been deleted; (ii) the transmembrane domain of the cytomegalovirus gB has been deleted; or (iii) the cytoplasmic domain and transmembrane domain of the cytomegalovirus gB have been deleted.
 18. The pharmaceutical composition of claim 3, wherein the cytomegalovirus tegument protein pp65 comprises an amino acid sequence that is at least 80% identical to SEQ ID NO:
 36. 19. The pharmaceutical composition of claim 3, wherein the cytomegalovirus tegument protein pp65 comprises an amino acid sequence that is at least 85% identical to SEQ ID NO:
 36. 20. The pharmaceutical composition of claim 3, wherein the cytomegalovirus tegument protein pp65 comprises an amino acid sequence that is at least 90% identical to SEQ ID NO:
 36. 21. The pharmaceutical composition of claim 3, wherein the cytomegalovirus tegument protein pp65 comprises an amino acid sequence that is at least 95% identical to SEQ ID NO:
 36. 22. The pharmaceutical composition of claim 3, wherein the cytomegalovirus tegument protein pp65 comprises an amino acid sequence that is at least 98% identical to SEQ ID NO:
 36. 23. The pharmaceutical composition of claim 3, wherein the cytomegalovirus tegument protein pp65 consists of an amino acid sequence that is 100% identical to SEQ ID NO:
 36. 24. The pharmaceutical composition of claim 1, wherein the first arenavirus viral vector, the second arenavirus viral vector, or both are lymphocytic choriomeningitis viruses.
 25. The pharmaceutical composition of claim 1, wherein the first arenavirus viral vector, the second arenavirus viral vector, or both are lymphocytic choriomeningitis virus Clone 13 strains.
 26. The pharmaceutical composition of claim 1, wherein the pharmaceutical composition is suitable to protect against a cytomegalovirus infection.
 27. A pharmaceutical composition comprising: a first infectious, replication-deficient arenavirus viral vector engineered to contain a genome with the ability to amplify and express its genetic information in infected cells but unable to produce further infectious progeny particles in normal, not genetically engineered cells, wherein the arenavirus open reading frame encoding the glycoprotein within the S segment is removed and replaced by a nucleotide sequence encoding a cytomegalovirus glycoprotein B (gB), wherein the cytoplasmic domain of the cytomegalovirus gB has been deleted; and a second infectious, replication-deficient arenavirus viral vector engineered to contain a genome with the ability to amplify and express its genetic information in infected cells but unable to produce further infectious progeny particles in normal, not genetically engineered cells, wherein the arenavirus open reading frame encoding the glycoprotein within the S segment is removed and replaced by a nucleotide sequence encoding a cytomegalovirus tegument protein pp65.
 28. The pharmaceutical composition of claim 27, wherein the cytomegalovirus gB consists of an amino acid sequence that is 100% identical to SEQ ID NO: 18, and the cytomegalovirus tegument protein pp65 consists of an amino acid sequence that is 100% identical to SEQ ID NO:
 36. 29. The pharmaceutical composition of claim 27, wherein both the first arenavirus viral vector and the second arenavirus viral vector are lymphocytic choriomeningitis viruses. 